UI changes to be inline with latest v0 (#16)

theme/blockly.less

@@ -19,8 +19,6 @@ div.blocklyTreeRow {
     border-radius:8px;
     box-shadow: inset 0 -1px 0 0 #ecf0f1;
 
-    margin-bottom: 0px !important;
-
     -webkit-transition-property: background-color; /* Safari */
     -webkit-transition-duration: 1s; /* Safari */
     transition-property: background-color;
@@ -52,6 +50,10 @@ span.blocklyTreeLabel {
     border-radius: 10px;
 }
 
+.blocklyFlyoutBackground {
+    fill: #42495F !important;
+}
+
 /* Mobile */
 @media only screen and (max-width: @largestMobileScreen) {
     .blocklyToolboxDiv, .monacoToolboxDiv {