Add proposal category, tags, badges to JSON export
Merge pull request #502 from nidico/feature-export-proposal-category-tags-badges

Add proposal category, tags, badges to JSON export
arrow links for instance and mildestone (continues #496)
stop using arrows in comment buttons
dont change comment button size on hover
mv comment_form from forms to comment
fix nested comment_form
fix spacing
nest comment_actions
fix comment buttons color
fix comment button vertical align
fixup nest comment_actions

without this, comments inside the paper overlay as well as
paper_actions in the paper list below proposals are broken
fix selection overlay votes and history tabs
fixup 576bea7 arrow links for instance and mildestone (continues #496)
use compass executable instead if compile_stylesheet
fixup 80e7178 fix spacing
typo fixup
remove leftover ipdb
use working example in configuration file
Workaround encoding problem in optional_attributes