Warnings tested with warnings.catch_warnings infrastructure.

Until there's some explanation as to why assertWarns method is failing,
this seems to be the only way forward.
Merge branch 'issue228' into devel
Merge branch 'devel' of https://github.com/quintusdias/glymur into devel

Conflicts:
	glymur/test/test_jp2box_jpx.py
	glymur/test/test_jp2k.py
	glymur/test/test_opj_suite.py
Removed apparently unreachable XML code for 2.6.
Improved warning message when brand is not proper.  #232
Removed two tests that we chose not to run because of stderr issues.

They produce too much output on stderr, it would make interpreting test
results difficult.
Updated versioning for pending 0.6.0 release.  Removed documentation cruft.
Merge branch 'issue232' into devel