Restructured frontpage. Moved auth sourc test into core. Improved the portal...

Restructured frontpage. Moved auth sourc test into core. Improved the portal module (started using it on the frontpage). frontpage hook is adjusted to fit new frontpage structure, and links updated.

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@1722 44740490-163a-0410-bde0-09ae8108e29a