Make the composer and TopicCreator use category id instead of category name

Also fixes #1171
Added backwards compatibility for topic creation
Use Discourse.Resolver to load mobile templates when they exist
Detect whether to use mobile view. Session var mobile_view can override automatic detection.
Create a mobile css manifest
Store mobile flag in Discourse.Session instead of Discourse
Replaced delegator methods with Forwardable def_delegator in Topic
Restructure the app/assets/stylesheets directory
rename application.css.erb to desktop.css.erb
Add imagemagick dependency
clockwork is not used anymore
fix user_name_suggester spec
Update German client-side translations.
Merge pull request #1400 from eparreno/fix_user_name_suggester_specs

fix user_name_suggester spec
Merge pull request #1399 from ZogStriP/patch-2

clockwork is not used anymore
Merge pull request #1398 from ZogStriP/patch-1

Add imagemagick dependency
Merge pull request #1392 from einarj/use_topic_delegators

Replaced delegator methods with Forwardable def_delegator in Topic
Revert "Replaced delegator methods with Forwardable def_delegator in Topic"

This reverts commit 3ed037940f464bc1ab32c0751dfe7df476ac31cb.
Better API for parsing out blocks in the parser.
Update German server-side translations.