Remove 'editor-colors' class from lines and gutter for mini editors

Having the editor-colors class on these elements was causing the theme
to be applied to lines in mini editors in the settings view, which
caused a black inset box to appear with dark syntax themes.

This was added to give the lines an opaque background which was supposed
to enable sub pixel anti-aliasing despite being on the GPU, but it
didn't seem to be working. Perhaps we can revisit this issue after the
Chrome 35 upgrade to see if sub pixel antialiasing works with opaque
backgrounds afterward.

src/gutter-component.coffee

@@ -19,9 +19,7 @@ GutterComponent = React.createClass
     {scrollHeight, scrollViewHeight, onMouseDown} = @props
 
     div className: 'gutter', onClick: @onClick, onMouseDown: onMouseDown,
-      # The line-numbers div must have the 'editor-colors' class so it has an
-      # opaque background to avoid sub-pixel anti-aliasing problems on the GPU
-      div className: 'gutter line-numbers editor-colors', ref: 'lineNumbers', style:
+      div className: 'gutter line-numbers', ref: 'lineNumbers', style:
         height: Math.max(scrollHeight, scrollViewHeight)
         WebkitTransform: @getTransform()
 

src/lines-component.coffee

@@ -26,9 +26,7 @@ LinesComponent = React.createClass
         width: scrollWidth
         WebkitTransform: @getTransform()
 
-    # The lines div must have the 'editor-colors' class so it has an opaque
-    # background to avoid sub-pixel anti-aliasing problems on the GPU
-    div {className: 'lines editor-colors', style},
+    div {className: 'lines', style},
       div className: 'placeholder-text', placeholderText if placeholderText?
       HighlightsComponent({editor, highlightDecorations, lineHeightInPixels, defaultCharWidth, scopedCharacterWidthsChangeCount, performedInitialMeasurement})