profile page: icon and hover explanation for auths

![screen shot 2014-10-16 at 11 07 00](https://cloud.githubusercontent.com/assets/464192/4660066/df75e788-5513-11e4-9b50-85cc0be3afc5.png)



If the contributor already used this particular branch before the final merge that is another issue.. you can close this and open another clean PR then :P but I would like to have cleaner PRs.. in another case if there were lots of files back and forth I would like not to have the bad history in it.. and grow the repo for no reason.. and the same applies to most of the PRs.. unless there are more staged changes :)