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
Restructure the app/assets/stylesheets directory
rename application.css.erb to desktop.css.erb
Add link in hamburger menu to switch between mobile and desktop views
FIX: Index out of range error

Fixes 'index out of range error' that occurs when viewing a user's
profile page when they haven't yet posted a reply or created a topic
and is @mentioned in a topic.
Extracted a fake_admin method
Add "nose" faces to the translations table

as per http://meta.discourse.org/t/use-more-standard-smiley-codes-instead-of-smile/1822/44
Add span.btn-text around 'Reply' text in the post menu
Restructure login form for mobile
If mobile view, don't switch to small logo in the header when scrolled down in a topic
Merge pull request #1408 from riking/patch-1

Add "nose" faces to the translations table
FIX: missing comma
Merge pull request #1407 from einarj/extract_fake_admin_method

Extracted a fake_admin method
Change the way nuked users' posts are handled. Allow null in the user_id column of posts. Show these posts in the posts stream.
Topic can have null user_id when user was nuked