Added montage script for python version

[Blizihguh]

The included montage script doesn't seem to work with the Python version. Specifically, the Python version outputs files named [filename][version].[ext], whereas the script is expecting CB[version]_[filename.ext]. I don't know if the C++ is the same way, since I haven't used it, but I assume the original script works there. Anyway, I fixed the script to work with Python.

Changes:

• Filename format now matches the Python output
• Included usage info and separate args for filename and extension, since the output format kind of requires it
• Script now runs Peacock.py directly instead of requiring the user to do it, so batch jobs only require you to run the script