final changes to codemirror styling, and clean up style for settings button clearing

cms/static/sass/views/_unit.scss

@@ -677,7 +677,6 @@ body.course.unit {
 
       select {
         @include box-shadow(0 1px 2px $shadow-l1 inset);
-        background: none repeat scroll #F2F2F2;
 
         &:focus {
           @include box-shadow(0 0 1px $shadow);
@@ -692,7 +691,6 @@ body.course.unit {
 
       .action.setting-clear {
         @include font-size(11);
-        background-color: $gray-l4;
         color: $gray;
         width: 25px;
         height: 25px;
@@ -702,7 +700,7 @@ body.course.unit {
         margin: 0 10px;
         box-shadow: none;
         text-shadow: none;
-        border: 1px solid $gray-l4;
+        border: 1px solid $gray-l1;
 
         &:hover {
           @include box-shadow(0 1px 1px $shadow);

common/lib/xmodule/xmodule/css/codemirror/codemirror.scss

@@ -2,5 +2,4 @@
   background: #fff;
   font-size: 13px;
   color: #3c3c3c;
-  padding: 15px;
 }
\ No newline at end of file

common/static/js/vendor/CodeMirror/codemirror.css

 .CodeMirror {
   line-height: 1em;
   font-family: monospace;
+  padding: 15px;
 }
 
 .CodeMirror-scroll {