Content Editor Layout Stabilization

CSS changes to make the layout consistent between browsers and less
prone to breakage.
Macro dropdown menu consistency

Make the macro dropdown menu consistent across browsers and fix the
positioning so it doesn't get cut off by elements to the right of it.
Remove unnecessary comment
Re-implement setSRStyleToggleVisibility on macros
Check if div exists before getting its height

In Big Editor, check if comment tools are enabled while getting the
height of the editor wrapper div.
Merge pull request #1452 from githue/commentBoxLayout

Content Editor Layout Stabilization