Adding a SIMPLESAML_INCPREFIX parameter before the inclusion of new files. This workaround was neccessary for university of oslo to make simplesamlphp work when ini_Set was not available.

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@353 44740490-163a-0410-bde0-09ae8108e29a