Improvement to debuglogging logging in general, handling of illegal input to...

Improvement to debuglogging logging in general, handling of illegal input to saml interfaces, improved error handling, better language support, collected all error messages in one dictionary file. +++

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@308 44740490-163a-0410-bde0-09ae8108e29a