put an upper limit on allowed ratio of failed chmod/chown operations
set group ID already on, if a group was specified
add debug info
Merge branch 'develop' into chgrp_fail
Merge branch 'develop' into chgrp_fail

Conflicts:
	easybuild/tools/filetools.py

also fixed remarks along the way
fix merge fail
Merge pull request #527 from boegel/chgrp_fail

set group id early on, and make eb aware of consistent chmod/chown failures