Merge branch 'master' into devel
JPEG2000SignatureBox can now has simple constructor call.
Added FileTypeBox default constructor defaults.
Use absolute rather than relative "up-the-ladder" imports.

This eases the problem of running the unittests via the command line
with "python -m unittest discover -s /start/path".  #53
Added default ImageHeaderBox case.
Added defaults to ColourSpecificationBox class
Added defaults for ContiguousCodestreamBox and JP2HeaderBox.
Starting on the _write method.
Success with default conversion from j2c to jp2.
Changed "tojp2" to "wrap".  Added goodstuff.j2k
Refactored configuration tests into new file.
Moved configuration file parsing back to lib.openjp2
Added runtests function to discover and run tests from within python.
Updated docs to reflect running tests from within python.
Merge branch 'issue53' into devel
Closes #63
Closes #62
Closes #61
Closes #60
Closes #59