Merge branch 'master' into devel
Reworked warning tests, closes #245.

Using 3.x warning infrastructure to verify warnings.  Using old 2.x
infrastructure to suppress warnings when the point of the test is not
the warning itself but something else.

All tests for warnings moved into glymur.test.test_glymur_warnings.
Merge branch 'issue245' into devel
Skipping failing test.  Closes #249

Test was failing already in openjpeg's own test suite on 1.5.2 and
2.0.0.  Best to just skip the test for those configurations.
Merge branch 'issue249' into devel
Removed duplicated warning tests.  Closes #250.
Removed test_ETS_C1P0_p0_07_j2k.  Closes #251

Test has always failed, so just remove it.
Merge branch 'issue251' into devel
Need to use extra care on skimage.io.plugin('freeimage'...)
Merge branch 'issue253' into devel
Basic functionality and UTs are in.
Documentation for slicing.
Must skip warning tests if version of six is < 1.7.
Merge branch 'issue255' into devel
Finesses the check of skimage.io

If on Anaconda and python3 and the scikit image version < 0.11, then
don't bother.  Otherwise, go back to prior try/except code for existance
of skimage.io and availability of freeimage backend, which fixes the
issue on Linux Mint.
Merge branch 'issue256' into devel
Rewrote jp2dump as an entry point console script.

Some printing UT refactoring was done.
Merge branch 'issue254' into devel
Restored set_parseoptions, get_parseoptions to glymur/__init__

Was mistakenly removed.
Add six to travis harness requirements.