remove win32 path stuff (not used anymore?) check for core 0.3.1 not 0.3.0 update Xv check for Xv_pic systems include...

Original commit message from CVS:
* remove win32 path stuff (not used anymore?)
* check for core 0.3.1 not 0.3.0
* update Xv check for Xv_pic systems
include text explaining it so check is not removed (again)
* remove GLIB_ vars since we don't set those vars
they are assumed to be in GST_ vars
* fix festival check - lib not used, just net connection to a server
* better FLAC test
* remove some core configure.ac leftovers