psot can be zero, meaning tile part extends to EOC marker.

Must pass in the codestream length to help figure this out.  #78
Updated affected tests.  Closes #78.
Minor doc bugs fixed, closes #79.
Merge branch 'issue79' into devel
Prepping for 0.2.4 bug fix release.
Qualified on centos 6.4.
Qualified on FC17.
Qualified on raspberry pi.
Qualified on mac, 2.6, 2.7, 3.3
Bumping setup.py to 0.2.4 official.
Merge branch 'release-0.2.4'
Merge branch 'master' into devel
Merge branch 'devel' of https://github.com/quintusdias/glymur into devel