Ilta-Saatana 2.0

Clean up code: handle complex nodes (sidebar items with timestamps and
other cruft) more intelligently, simplify IS script and selectors,
switch to JS indentation standard of 2 spaces.

Better builds: put the improved jQuery satanifier into a common script,
concatenate the "library" functions to the userscript during builds
instead of fetching them as a @require dependency.

Drop the Chrome extension: installation from outside the Chrome Web
Store is too hard. CBA build and upload there so just recommend
Tampermonkey.

I'd be surprised if anyone ever reads this commit message.