Fix setuppy

[kinow]

Running python setup.py install failed on my machine with:

running install
running build
running build_py
running install_lib
running install_data
error: can't copy 'practnlptools/embeddings/SENNA_SRL.c': doesn't exist or not a regular file

SENNA_SRL.c is located under practnlptools, but the current function to walk through the data_files directory seemed to be at fault. Used an example found online that seemed to work.

Thanks
Bruno