Replace HAML with SLIM
Update CHANGELOG
Improve english message

Fix the english message
Move info about removing gems to contributing file
Merge pull request #309 from Helabs/mg-gem-and-post

Move info about removing gems to contributing file.
Convert to haml
Merge branch 'slim-rails-mauro' into slim-rails

Conflicts:
	lib/pah/files/app/views/application/_flash_messages.html.slim
	lib/pah/files/app/views/layouts/application.html.slim
Some fixes on slim => haml
Merge pull request #311 from Helabs/slim-rails

Slim rails.

Closes #281.
Move changelog to correct place
Remove variables declaration from general scss.