hdf5_ep

[svn-r26681] Merge r26677 from trunk.

HDFFV-8957: h52gif crashes when run against one of our own examples 
The tool claimed it could handle 24bit images but there was no code to handle it.
(or might be there were but was removed by previous revisions.)
Also discovered that it does not accept multiple images nor -p for palette
as its user document and online help message indicated.

Solution: 
Added code to verify dimension sizes are within 8 bit raster images limit and
added tests to verify the tools correctness.
Need to update user document tool.

Tested: h5committested.