fix user icon

Stacked user icon on top of a circle icon. Also, if a logged in user
does not have a photo it shows the user icon instead of nothing.
Added customizable profile links

Customize the links that show up in the profile drop down when a user
is logged in. This follows the same pattern as the external site links.
Merge branch 'master' into fix_account_menu

Conflicts:
	README.md
	lib/biola_frontend_toolkit/configuration.rb
Merge pull request #2 from biola/fix_account_menu

Fix account menu