Links data

Hi Roman,

I think I have all of the links working except the one that requires user authentication.
I added icons instead of letters for the results page; I think it's more user-friendly, please tell me what you think.
I also installed a better less mixin library and made it so that grunt watches for changes in the less file--before you had to restart the server.

Major things I added:
-link generator mixin  that is used by the resources widget, the results widget, and the abstract widget to generate links (uses Giovanni's logic)
-resources widget, which displays both fulltext and data sources on the abstract page
-tests for link generator mixin and resources widget
-I added the font awesome library: I am going to replace all glyphicons from bootstrap with this library (there are still a mix  of the two in the current branch)
Alex, let's do the same for other less files (that we are not changing) - ie. the font-awesome etc. We don't need to commit them to a repo. thanks