Revert "Merge pull request #635 from adambutler/favicon-calendar"

This reverts commit afc64853751fe9b820ae5888db597bbf7e4db79a, reversing
changes made to ca6d180fe76ad028698017048d6c7d998cb188b2.

Favicon is not fully working see #701.
related https://github.com/24pullrequests/24pullrequests/pull/709#issuecomment-65238521

Conflicts:
	app/helpers/application_helper.rb