Adding dropup support to split buttons and navbar

* Documents the hidden .dropdown-menu.bottom-up option (to be used for dropups)
* Extends the .bottom-up class to carets and all relevant caret styles
* Adds .dropdown-menu.pull-right class for right-aligned dropdowns and dropups
* Adds examples and some information to the "split dropdown" and "navbar" sections of the Docs

less/button-groups.less

@@ -136,6 +136,7 @@
 .success {
   .caret {
     border-top-color: @white;
+    border-bottom-color: @white;
     .opacity(75);
   }
 }

less/dropdowns.less

@@ -29,6 +29,14 @@
   .opacity(30);
   content: "\2193";
 }
+
+  // Allow for caret to show up (goes well with dropup-menus)
+  &.bottom-up {
+    border-top: 0;
+    border-bottom: 4px solid @black;
+    content: "\2191";
+  }
+
 .dropdown .caret {
   margin-top: 8px;
   margin-left: 2px;
@@ -68,7 +76,13 @@
   &.bottom-up {
     top: auto;
     bottom: 100%;
-    margin-bottom: 2px;
+    margin-bottom: 1px;
+  }
+
+  // Aligns the dropdown menu to right
+  &.pull-right {
+    right: 0;
+    left: auto;
   }
 
   // Dividers (basically an hr) within the dropdown

less/navbar.less

@@ -253,11 +253,27 @@
     left: 10px;
   }
 }
-
+// Menu position and menu caret support for dropups via extra bottom-up class
+.navbar .dropdown-menu.bottom-up {
+  &:before {
+    border-top: 7px solid #ccc;
+    border-top-color: rgba(0, 0, 0, 0.2);
+    border-bottom: 0;
+    bottom: -7px;
+    top: auto;
+  }
+  &:after {
+    border-top: 6px solid #ffffff;
+    border-bottom: 0;
+    bottom: -6px;
+    top: auto;
+  }
+}
 // Dropdown toggle caret
 .navbar .nav .dropdown-toggle .caret,
 .navbar .nav .open.dropdown .caret {
   border-top-color: @white;
+  border-bottom-color: @white;
 }
 .navbar .nav .active .caret {
   .opacity(100);
@@ -276,7 +292,7 @@
 }
 
 // Right aligned menus need alt position
-.navbar .nav.pull-right .dropdown-menu {
+.navbar .nav.pull-right .dropdown-menu, .navbar .nav .dropdown-menu.pull-right {
   left: auto;
   right: 0;
   &:before {

less/navs.less

@@ -227,6 +227,7 @@
 .nav .open.active .caret,
 .nav .open a:hover .caret {
   border-top-color: @white;
+  border-bottom-color: @white;
   .opacity(100);
 }