feat: enable onload callbacks (#414)

* refactor(examples): run ssr example from server

* chore: switch to babel for build

buble complains too much

* feat: enable loaded callbacks

feat: add skip option

* examples: add async-callback browser example

* examples: fix server

* examples(ssr): add reactive script with callback

* fix: also skip on ssr

* chore: remove unused var

* feat: only add mutationobserver if DOM is still loading

feat: disconnect mutation observer once DOM has loaded

* examples: pass vmid to loadCallback instead of el

* feat: also support load callbacks for link/style tags

* test: add unit tests for load

* test: add load e2e test

* chore: fix lint

* chore: remove unused files

* test: fix e2e load callback test

* test: fix attempt

* examples: ie9 compatiblity

destructuring doesnt work in ie9

* fix: add onload attribute on ssr

dont rely on mutationobserver

* chore: lint ci conf

* refactor: remove loadCallbackAttribute config option

test: fix coverage for load

* test: improve coverage

* fix: only use console when it exists (for ie9)

* chore: fix coverage

yarn.lock

@@ -1778,7 +1778,7 @@ acorn-globals@^4.1.0, acorn-globals@^4.3.2:
     acorn "^6.0.1"
     acorn-walk "^6.0.1"
 
-acorn-jsx@^5.0.0, acorn-jsx@^5.0.1:
+acorn-jsx@^5.0.0:
   version "5.0.1"
   resolved "https://registry.yarnpkg.com/acorn-jsx/-/acorn-jsx-5.0.1.tgz#32a064fd925429216a09b141102bfdd185fae40e"
   integrity sha512-HJ7CfNHrfJLlNTzIEUTj43LNWGkqpRLxm3YjAlcD0ACydk9XynzYsCBHxut+iqt+1aBXkx9UP/w/ZqMr13XIzg==
@@ -2534,20 +2534,6 @@ bser@^2.0.0:
   dependencies:
     node-int64 "^0.4.0"
 
-buble@^0.19.8:
-  version "0.19.8"
-  resolved "https://registry.yarnpkg.com/buble/-/buble-0.19.8.tgz#d642f0081afab66dccd897d7b6360d94030b9d3d"
-  integrity sha512-IoGZzrUTY5fKXVkgGHw3QeXFMUNBFv+9l8a4QJKG1JhG3nCMHTdEX1DCOg8568E2Q9qvAQIiSokv6Jsgx8p2cA==
-  dependencies:
-    acorn "^6.1.1"
-    acorn-dynamic-import "^4.0.0"
-    acorn-jsx "^5.0.1"
-    chalk "^2.4.2"
-    magic-string "^0.25.3"
-    minimist "^1.2.0"
-    os-homedir "^2.0.0"
-    regexpu-core "^4.5.4"
-
 buffer-from@^1.0.0:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/buffer-from/-/buffer-from-1.1.1.tgz#32713bc028f75c02fdb710d7c7bcec1f2c6070ef"
@@ -3323,7 +3309,7 @@ copy-descriptor@^0.1.0:
   resolved "https://registry.yarnpkg.com/copy-descriptor/-/copy-descriptor-0.1.1.tgz#676f6eb3c39997c2ee1ac3a924fd6124748f578d"
   integrity sha1-Z29us8OZl8LuGsOpJP1hJHSPV40=
 
-copy-webpack-plugin@^5.0.2:
+copy-webpack-plugin@^5.0.2, copy-webpack-plugin@^5.0.3:
   version "5.0.3"
   resolved "https://registry.yarnpkg.com/copy-webpack-plugin/-/copy-webpack-plugin-5.0.3.tgz#2179e3c8fd69f13afe74da338896f1f01a875b5c"
   integrity sha512-PlZRs9CUMnAVylZq+vg2Juew662jWtwOXOqH4lbQD9ZFhRG9R7tVStOgHt21CBGVq7k5yIJaz8TXDLSjV+Lj8Q==
@@ -5044,6 +5030,13 @@ get-pkg-repo@^1.0.0:
     parse-github-repo-url "^1.3.0"
     through2 "^2.0.0"
 
+get-port@^5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/get-port/-/get-port-5.0.0.tgz#aa22b6b86fd926dd7884de3e23332c9f70c031a6"
+  integrity sha512-imzMU0FjsZqNa6BqOjbbW6w5BivHIuQKopjpPqcnx0AVHJQKCxK1O+Ab3OrVXhrekqfVMjwA9ZYu062R+KcIsQ==
+  dependencies:
+    type-fest "^0.3.0"
+
 get-stdin@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/get-stdin/-/get-stdin-4.0.1.tgz#b968c6b0a04384324902e8bf1a5df32579a450fe"
@@ -7033,13 +7026,6 @@ magic-string@^0.25.2:
   dependencies:
     sourcemap-codec "^1.4.4"
 
-magic-string@^0.25.3:
-  version "0.25.3"
-  resolved "https://registry.yarnpkg.com/magic-string/-/magic-string-0.25.3.tgz#34b8d2a2c7fec9d9bdf9929a3fd81d271ef35be9"
-  integrity sha512-6QK0OpF/phMz0Q2AxILkX2mFhi7m+WMwTRg0LQKq/WBB0cDP4rYH3Wp4/d3OTXlrPLVJT/RFqj8tFeAR4nk8AA==
-  dependencies:
-    sourcemap-codec "^1.4.4"
-
 make-dir@^2.0.0, make-dir@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/make-dir/-/make-dir-2.1.0.tgz#5f0310e18b8be898cc07009295a30ae41e91e6f5"
@@ -7894,11 +7880,6 @@ os-homedir@^1.0.0:
   resolved "https://registry.yarnpkg.com/os-homedir/-/os-homedir-1.0.2.tgz#ffbc4988336e0e833de0c168c7ef152121aa7fb3"
   integrity sha1-/7xJiDNuDoM94MFox+8VISGqf7M=
 
-os-homedir@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/os-homedir/-/os-homedir-2.0.0.tgz#a0c76bb001a8392a503cbd46e7e650b3423a923c"
-  integrity sha512-saRNz0DSC5C/I++gFIaJTXoFJMRwiP5zHar5vV3xQ2TkgEw6hDCcU5F272JjUylpiVgBrZNQHnfjkLabTfb92Q==
-
 os-locale@^3.0.0, os-locale@^3.1.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/os-locale/-/os-locale-3.1.0.tgz#a802a6ee17f24c10483ab9935719cef4ed16bf1a"
@@ -9313,13 +9294,13 @@ ripemd160@^2.0.0, ripemd160@^2.0.1:
     hash-base "^3.0.0"
     inherits "^2.0.1"
 
-rollup-plugin-buble@^0.19.8:
-  version "0.19.8"
-  resolved "https://registry.yarnpkg.com/rollup-plugin-buble/-/rollup-plugin-buble-0.19.8.tgz#f9232e2bb62a7573d04f9705c1bd6f02c2a02c6a"
-  integrity sha512-8J4zPk2DQdk3rxeZvxgzhHh/rm5nJkjwgcsUYisCQg1QbT5yagW+hehYEW7ZNns/NVbDCTv4JQ7h4fC8qKGOKw==
+rollup-plugin-babel@^4.3.3:
+  version "4.3.3"
+  resolved "https://registry.yarnpkg.com/rollup-plugin-babel/-/rollup-plugin-babel-4.3.3.tgz#7eb5ac16d9b5831c3fd5d97e8df77ba25c72a2aa"
+  integrity sha512-tKzWOCmIJD/6aKNz0H1GMM+lW1q9KyFubbWzGiOG540zxPPifnEAHTZwjo0g991Y+DyOZcLqBgqOdqazYE5fkw==
   dependencies:
-    buble "^0.19.8"
-    rollup-pluginutils "^2.3.3"
+    "@babel/helper-module-imports" "^7.0.0"
+    rollup-pluginutils "^2.8.1"
 
 rollup-plugin-commonjs@^10.0.1:
   version "10.0.1"
@@ -9369,7 +9350,7 @@ rollup-plugin-terser@^5.1.1:
     serialize-javascript "^1.7.0"
     terser "^4.1.0"
 
-rollup-pluginutils@^2.3.3, rollup-pluginutils@^2.5.0, rollup-pluginutils@^2.6.0, rollup-pluginutils@^2.8.1:
+rollup-pluginutils@^2.5.0, rollup-pluginutils@^2.6.0, rollup-pluginutils@^2.8.1:
   version "2.8.1"
   resolved "https://registry.yarnpkg.com/rollup-pluginutils/-/rollup-pluginutils-2.8.1.tgz#8fa6dd0697344938ef26c2c09d2488ce9e33ce97"
   integrity sha512-J5oAoysWar6GuZo0s+3bZ6sVZAC0pfqKz68De7ZgDi5z63jOVZn1uJL/+z1jeKHNbGII8kAyHF5q8LnxSX5lQg==