Added bundler.py to replace the existing RunBundler.sh bash script.

The Python script reduces the number of dependencies required by
the project, offers a parallel mode for extracting SIFT features,
and (should) increase portability (no more dependence on bash, ...).
bundler.py can be run to produce similar output to RunBundler.sh
(also just as slow):

  > bundler.py --verbose --no-parallel

The new Python module can also be imported into python modules
allowing access to the Bundler system from a series of convenience
functions.