Added file paths to the filters
Added pattern matching for the clean filter
Added checking the smudge filter

This check uses the .gitbig in the repository.
There might be issues with this - we should possibly check on commit to
ensure that the .gitbig file is committed along with new files??
Added pattern functions for staged .gitbig file
Added a header and a version number to db ids

This is so we can traverse the repo and get files which are managed by
git-big. It is (obviously) not 100% foolproof, and has issues with big
and little endian in its current state.
Re-ordered some parameters

This makes these parameters match the overall program structure.