Rejigger the shortcuts bar

clean up aisle 1
Part 2
Font size importance
Oooh, new arrow glyphs and nice alignment

Including subreddit compatibility additions.
Remove test code
Adjustments and browser compatibility

Tested on dozens of subreddits with Chrome and Firefox on Windows. No
known display issues presently.
A more robust if statement
Change of tactic

Found that some popular subs were being unreasonably strict and breaking
bg colors, so I'm putting my foot down. Now you can't not have a
bg-color.
Remove old if statement
Reduce width of shortcutEditButtons
Remove border
Move redrawShortcuts() to original place
Fewer lines affected and glyphs for + and x

Put the code for the buttons back in their original order so fewer lines
are affected, but maintain the desired ordering.
Merge pull request #1277 from githue/sr-header-bar-height

Fixes for the shortcuts bar