Fix language negotiations

This fixes what 59d0765841837ca641cd1cc69d3349d6e8d077fd intended to
fix.

Babel language negotiation can only compare language codes using the
same separator. As we use underscores and browsers send dashes, we now
convert our static list to use dashes as well for the negotiation.

The previous "fix" of adding {'pt':'pt_BR'} as locale alias actually
replaced the original babel alias dict and therefore only had the
intended effect by accident and only Portuguese survived the negotiation
process! The next commit makes proper use of the LOCALE_ALIASES keyword
argument.
Show pt_BR if pt is requested

As we only have Brazilian Portuguese, we show that when Portuguese (pt)
is requested.
i18n: update translations
chmod -x on compass config
Merge pull request #895 from nidico/feature-fix-language-negotiation

Feature fix language negotiation
include more events in category events

Add support for proposal events (including comments) and one level of
page nesting.
mv category events query to helper function
refactor: split subqueries and better names
Merge pull request #896 from xi/feature-category-proposal-events

category proposal events
i18n: extract messages
i18n: update translations
add CHANGES for 2.4.2
Allow to define 'hide_individual_votes' on instance level

This is as experimental as the global setting.
Merge pull request #897 from nidico/feature-hide-individual-votes-per-instance

Allow to define 'hide_individual_votes' on instance level
add hologram styleguide generator
create some example CSS docs
style styleguide page navigation
Merge pull request #898 from xi/feature-hologram

hologram styleguide
Don't try to solr index form-feed characters

This makes sure we don't try to solr index form-feed characters. The
same has been done for vertical-tab characters in
c588a8bd6d96252325eadd6ee87e1dcc073087fc.
Don't allow amendment creation for non-joined members