Set up sys.path properly in FileDriver to enable imports.
Merge branch 'master' of https://github.com/tarasglek/pydoop into FileDriver
The combine function shouldn't recombine, so keep combine results separate from map results and merge them after we're finished mapping.
Make FileDriver work with no combine function.
Merge pull request #11 from bsmedberg/FileDriver

File driver changes for proper importing and combining