Fixed doctest/webdb.txt to be compliant reStructuredText
Added Makefile rule 'docs' to compile documentation
Renamed response.StreamObj and StreamPath to stream and stream_path respectively
Fixed typo in Table.__repr__
Fixed comparisons to None/NULL in webdb
webdb.drivers.base: Comparing None/NULL values uses IS or IS NOT
webdb/__init__.py: Selection.one returns None if it encounters StopIteration
silk.webreq, silk.webreq.uri: URI.path is the original string, request.args splits it