remove unnecessary require calls - the ownCloud class loader is supposed...

... to take care of this

@schiesbn this mainly touches your code base - please have a look

What's the reason for these changes?
Within our phpunit configuration we already require lib/base.php which fires up the whole ownCloud instance including the class loader. There is no need to require all these files explicitly.

Further reviewers please @PVince81 @icewind1991 @bantu THX