can make comments on training questions.
add view to show training comments.
having new comment subscription model work.
show Facebook image in activities
Merge branch 'training_comment' of github.com:Coursemology/coursemology.org into dev/raymoond

Conflicts:
	app/views/modules/commentable/_commentable_std_answer.html.erb
merge
fixes for commenting summary after adding training comments
refactor
precompiled assets