Merge branch 'devel' into issue130
colr, flst, and pclr box.  #130

The pclr box is the problematic one.  If the box length is wrong, then
it's hard to reliably parse when reading just one raw buffer.
Merge branch 'issue130' of https://github.com/quintusdias/glymur into issue130

Conflicts:
	glymur/jp2box.py
Variable renaming.  #130
Removed one read statement, using struct.unpack_from.   #130