Update python docstring for release
Fix an issue with gdcmimg and multiple input files.

This commit closes issue #333 and add proper behavior for handling or multiple uncompressed files to gdcmimg
As part of this cleanup the guess modality behavior was extended (lifted from VTK implementation) and moved to core gdcm class.
Rename man pages to have dox extension

See:
https://bugs.debian.org/759957#37
for details
Remove man file extension since ignored now

Update doxygen input file