MDL-38661 Course: Add JS category expander.

This adds a category expanded which:
* fetches child content in a category tree if it has not already been loaded;
* toggles relevant classes on the category node to show and hide child content; and
* applies appropriate animations to improve user experience.

theme/bootstrapbase/less/moodle/core.less

@@ -141,6 +141,29 @@ a.autolink.glossary:hover {
 .jsenabled .collapsed .collapsibleregioninner {
     visibility: hidden;
 }
+.collapsible-actions {
+    display: none;
+    text-align: right;
+}
+.dir-rtl .collapsible-actions {
+    text-align: left;
+}
+.jsenabled .collapsible-actions {
+    display: block;
+}
+.collapsible-actions .collapseexpand {
+    padding-left: 20px;
+    background: url([[pix:t/collapsed]]) 2px center no-repeat;
+}
+.dir-rtl .collapsible-actions .collapseexpand {
+    padding-right: 20px;
+    padding-left: 0;
+    background: url([[pix:t/collapsed_rtl]]) right center no-repeat;
+}
+.collapsible-actions .collapse-all,
+.dir-rtl .collapsible-actions .collapse-all {
+    background-image: url([[pix:t/expanded]]);
+}
 .yui-overlay .yui-widget-bd {
     background-color: #FFEE69;
     border: 1px solid #A6982B;
@@ -2110,3 +2133,11 @@ ul.dragdrop-keyboard-drag li {
     width: 12px;
     height: 12px;
 }
+
+a.disabled:hover,
+a.disabled {
+    text-decoration: none;
+    cursor: default;
+    font-style: italic;
+    color: #808080;
+}

theme/bootstrapbase/less/moodle/course.less

@@ -498,26 +498,6 @@ span.editinstructions {
     font-size: @fontSizeSmall;
 }
 
-.course_category_tree .controls {
-    visibility: hidden;
-}
-.course_category_tree .controls div {
-    display:inline;
-    cursor:pointer;
-}
-.jsenabled .course_category_tree .controls {
-    visibility: visible;
-}
-.course_category_tree .controls {
-    margin-bottom:5px;
-    text-align:right;
-    float:right;
-}
-.course_category_tree .controls div {
-    padding-right:2em;
-    font-size:75%;
-}
-
 .course_category_tree .category>.info .name {
     background-image:url([[pix:moodle|t/collapsed_empty]]);
     background-repeat: no-repeat;
@@ -548,6 +528,7 @@ span.editinstructions {
     padding:0;
     margin:3px 0;
     margin-bottom:3px;
+    clear: both;
 }
 .course_category_tree.frontpage-category-names .category >.info {
     background:none;

theme/bootstrapbase/less/moodle/forms.less

@@ -51,29 +51,6 @@ form {
 .jsenabled .mform .collapsed .fcontainer {
     display: none;
 }
-.mform .collapsible-actions {
-    display: none;
-    text-align: right;
-}
-.dir-rtl .mform .collapsible-actions {
-    text-align: left;
-}
-.jsenabled .mform .collapsible-actions {
-    display: block;
-}
-.mform .collapsible-actions .collapseexpand {
-    padding-left: 20px;
-    background: url([[pix:t/collapsed]]) 2px center no-repeat;
-}
-.dir-rtl .mform .collapsible-actions .collapseexpand {
-    padding-right: 20px;
-    padding-left: 0;
-    background: url([[pix:t/collapsed_rtl]]) right center no-repeat;
-}
-.mform .collapsible-actions .collapse-all,
-.dir-rtl .mform .collapsible-actions .collapse-all {
-    background-image: url([[pix:t/expanded]]);
-}
 
 .mform .fitem .fitemtitle div {
     display: inline;