Greater standardization of sizing terminology

In class names:
* large => lg
* small => sm
* mini => xs ("Extra small")

In screen size categories:
* Tiny => Extra small

less/forms.less

@@ -218,14 +218,14 @@ input[type="number"] {
 // horizontal sizing, wrap controls in the predefined grid classes. `<select>`
 // element gets special love because it's special, and that's a fact!
 
-.input-large {
+.input-lg {
   height: @input-height-large;
   padding: @padding-large-vertical @padding-large-horizontal;
   font-size: @font-size-large;
   line-height: @line-height-large;
   border-radius: @border-radius-large;
 }
-.input-small {
+.input-sm {
   height: @input-height-small;
   padding: @padding-small-vertical @padding-small-horizontal;
   font-size: @font-size-small;
@@ -234,18 +234,18 @@ input[type="number"] {
 }
 
 select {
-  &.input-large {
+  &.input-lg {
     height: @input-height-large;
     line-height: @input-height-large;
   }
-  &.input-small {
+  &.input-sm {
     height: @input-height-small;
     line-height: @input-height-small;
   }
 }
 textarea {
-  &.input-large,
-  &.input-small {
+  &.input-lg,
+  &.input-sm {
     height: auto;
   }
 }