Add comments to button material theme

src/themes/material/elements/button.variables

@@ -13,7 +13,7 @@
 
 @verticalPadding   : 0.8em;
 @horizontalPadding : 0.8em;
-@borderRadius      : 0.153846153em;
+@borderRadius      : @relative2px;
 @color             : #222222;
 @fontWeight        : normal;
 @textTransform     : none;
@@ -56,6 +56,7 @@
       Variations
 --------------------*/
 
+/* Basic */
 @basicBorderSize: 0px;
 @basicBorderRadius: 4px;
 @basicColoredBorderSize: 1px;
@@ -67,21 +68,28 @@
 @basicActiveBackground: #FFFFFF;
 @basicActiveBoxShadow: 0px 0px 0px 1px rgba(0, 0, 0, 0.2);
 
+/* Labeled */
 @labeledIconBackgroundColor: transparent;
 @labeledIconWidth: 2em;
 
+/* Colored */
 @coloredBackgroundImage : @subtleGradient;
 @coloredBoxShadow       : 0px 0px 0px 1px rgba(0, 0, 0, 0.1) inset;
 
+/* Primary */
 @primaryColor       : #4184F3;
 @primaryBoxShadow   : 0px 0px 0px 1px #0157E4 inset;
 
+/* Secondary */
 @secondaryColor           : #EEEEEE;
 @secondaryBackgroundImage : @backgroundImage;
 @secondaryTextColor       : @textColor;
 @secondaryBoxShadow       : @borderBoxShadow;
 
+/* Emotive */
 @positiveColor: #3D9400;
 @negativeColor: #D34836;
+
+/* Inverted */
 @invertedBorderSize: 1px;