added a button to add a snippet on sources#show
APS & DB: pressing add snippet will print selected text of multiple divs to the console
APS & DB: refactored text selection process
AS & dan: display add snippet form only when text is selected
Merge branch 'master' into snippet/import-selection

Conflicts:
	app/assets/stylesheets/snippet.css.scss
APS & DB: user can add preexisting topic while creating snippet
Merge pull request #35 from gopher-snakes-2013/snippet/import-selection

APS & DB: Snippet/import selection