Various cleanups to Ubuntu installation instructions:

* Avoid editing /etc/apt/sources.list add nginx repo, instead create
  /etc/apt/sources.list.d/nginx.list

* Avoid editing /etc/nginx/nginx.conf, instead put server_name_hash_buckets
  setting into discourse.conf

* Proper-case Discourse when it is referring to the product name, so that all
  the lowercase references are to the user created during the installation
Address @Supermathie's concerns in PR1430
updated spanish translation
Switch from MMM D to D MMM to separate from year

Additionally, in German, the format is 'D. MMM'.
Merge pull request #2107 from riking/change-date-format

Switch from MMM D to D MMM to separate from year
Poll - French Translation

French translation for the plugin Poll
Merge pull request #2108 from Onaldanm/plugin-poll-fr

Poll - French Translation
Add a test to make sure the poll prefix translation can be a regex.
FIX: encoding on FR translations
FIX: shortDate tests
Merge pull request #2109 from vikhyat/poll-plugin

Add a test to make sure the poll prefix translation can be a regex
FEATURE: gzip backups using best compression
update sass, cause compilation of css is getting really slow
Revert "update sass, cause compilation of css is getting really slow". Getting "RuntimeError: can’t modify frozen object" when logged in as admin.
FIX: revision history UI
TRIVIAL: remove useless condition
Remove ember-renderspeed JS file
going back to the white on blue new post notification badges
Merge pull request #2110 from awesomerobot/master

going back to the white on blue new post notification badges
Refactor find_relevant_topics and find_categories

This breaks down two private methods into smaller methods for
readability. This also moves logic into the Category model class.