Feature/andy/pythonify

@stringfellow @chrisewing 
This is an initial attempt to bring the OSM -> SHP conversion component up to PEP8. It would be helpful to me to have a code review at this stage and get some feedback.

The unit tests are mostly stubs at the moment. A lot of the code is entirely procedural. To an extend this feels right given the non-interactive batch-task nature of what it does. However it is not intermediately obvious to me how this should be unit tested without needing writing a vast amount of mock objects - which instinctively seem wrong. (How to create tests that enclose the function of each entire source file is more obvious - though it that so useful?)

Many thanks, Andy