Fixed building python modules on MacOS X.

Python modules now build successfully using either MacPorts gcc (make)
or Xcode command-line tools (make CC=cc) and MacPorts SWIG. Use of a
matching Python installation (i.e. MacPorts or native respectively) is
recommended.
Added .gitattributes to force FITS files to be treated as binary.
Added two-channel input data for demo program.
Corrected unit test names.
Fixed memory leak in oimerge.
Merge branch 'master' into oifits2

Conflicts:
	oimerge.c

Resolved conflict on merge of master branch bugfixes into oifits2
feature branch.