Fix failing builds for specs:

* post controller spec
* topics controller spec

Fixes #464
Fix deprecation on 'stub'.
Decorate the user class in seed.rb in case it hasn't been yet.

This fixes #495.

See https://github.com/bricker/forem-generator-error for more
information.

Fixes #537
select2 v3.5.4

Fixes #530
Fixes #540

Conflicts:
	forem.gemspec
Topics are now accessible only within the context of their forums

This patch reworks the routes for all topics requests so that they're scoped by the forum. This is going to make my multi-tenancy branch easier.

I've also taken the liberty to fix the (sometimes) failing permission tests by converting them into either controller specs or view specs

I ran the tests four times before committing this and all four times they passed.
Forem now defines its own layout

This can be changed to use a different layout, but that other layout should require the forem assets.

Please see the updated documentation for more information: https://github.com/radar/forem/wiki/Theming
Update for Bootstrap 3
Fixed a regression introduced by commit #54c57330c419a597078170143398b33427114ae0

Conflicts:
	app/models/forem/topic.rb
Added a regression test on the topic nodel
Add sass-rails and coffee-rails dependencies

Necessary for new forem layout added recently
Include forem_atom_auto_discovery_link_tag in the default layout
Use class for flash tag in default application layout
Add asset generation step mention to install generator
Bump database_cleaner and devise versions
Add Lab Nation to Places using Forem
Tests and implementation (WIP for #451)
Methods in nil user
Updated README