Include all necessary files in the source dist
Include all necessary files in the source dist

This simplifies some of the lines in the MANIFEST file and catches some
non-python files that were missed in the last version.

manthey/girder,jbeezley/girder,jbeezley/girder,girder/girder,girder/girder,manthey/girder,jbeezley/girder,girder/girder,girder/girder,manthey/girder,RafaelPalomar/girder,kotfic/girder,RafaelPalomar/girder,kotfic/girder,kotfic/girder,kotfic/girder,Kitware/girder,manthey/girder,RafaelPalomar/girder,Kitware/girder,RafaelPalomar/girder,jbeezley/girder,Kitware/girder,Kitware/girder,kotfic/girder,RafaelPalomar/girder