Night mode tweaks

Permalinked comment background/visited links in comments
More night mode tweaks

Increased contrast on 'commentBoxes'
Night mode subreddit bar icons

Sort, left/right arrow, trash, add background colours
Night mode big editor tweaks

Main background/text and the bold/link/quote etc shortcuts
Inject night mode sooner

An attempt to mitigate the admittedly fleeting flash of white before
night mode is applied
More night mode tweaks

Fix for links within blockquotes/code colour
Merge pull request #350 from gavin19/master

Night mode tweaks