Fix opj_write_bytes_BE (#518)

[manisandro]

This patch, originally by @szukw000, fixes the issue where opj_compress + opj_decompress fails on bigendian systems.

[detonin]

@manisandro Many thanks for the PR.
@sharkcz I do not have access to any big endian machine: is there a way you could run the test suite with and without the patch and report results ? To run the test suite, you have to clone openjpeg-data repository, enable testing in cmake configuration, and indicate to cmake where to find openjpeg-data folder. Then, "make & make Experimental" launches the test suite and submits results to CDash dashboard (http://my.cdash.org/index.php?project=OPENJPEG). Let me know.

[mayeut]

This is related to #518 (already in the title but needed to properly create a link between the 2 it seems)

[szukw000]

@detonin, I have done both.

Site name: G5
Build name: Linux-(g5-3.16.0-4-powerpc64-#1-SMP-Debian-3.16.7-ckt11-1-(2015-05-24)-ppc64-GNU/Linux)

The first is without, the second with, the cio.c patch of #518.

winfried