Added Github's Octicons.
Added octions to navbar.
Added group icon to user list header.
Added search icon to search box in user list.
Added octicons to user list itself.
Fixed icon position.
Changed about icon.
Added sign in icon.
Added open door icon.
Added big hubot to admin welcome screen.
Replaced new user button text with icon.
Refined "This is you" label.
Added 'x' to delete operations.
Added checks if save buttons are enabled.
Added repo icon to about.
Changed about icon to package.

Because it was not fitting with about page’s repo icon.
Merge branch 'feature/octicons'