Restore font sizes

It seems the Chrome team defaults font-size to 75% now. Set font-size to
100% in the body css. Also, take this oportunity to split out css into
separate stylesheet files.
Address a few CSS layout issues
Add filter box to citation styles selector

Also, rearrange layout a bit.
Version 2.2.3
Fix citation styles box width
Version 2.2.4
Bubble formatting updates
Minor CSS formatting cleanup
Only show selectable resolver in bubble if enabled

Fixes issue where radio buttons for selectable default or custom
resolver showed even when entire option for custom resolver was
disabled.
Version 2.2.5
Correct meta buttons order in bubble
Add git-ignore for styles subdir
Display real style name in other styles selection

Update output_styles.sh script to output both style name (which is used
for ajax requests) and style title (human readable). Use the style title
in the filter box for the citation generator.
Version 2.2.6
Fix .gitignore directory syntax
Update citation generator to use full style list

With a filter and human readable styles, there is no longer a need to
separate the full list from a short list of styles.
Handle special characters in styles filter box

See comment here:
http://www.lessanvaezi.com/filter-select-list-options/#comment-809
Version 2.2.7
Add citeproc-js and locales to .gitignore
Bundle citeproc-js and generate citations in-house

Not all citation styles are supported by citeref and datacite. Instead,
use their application/citeproc+json content type to retrieve citation
meta and generate the citation in the extension, using citeproc-js.

ToDo: handle language selection:
http://gsl-nagoya-u.net/http/pub/citeproc-doc.html#instantiation-csl-engine