BPython, two bug fixes:

- #1911: http://projects.blender.org/tracker/?func=detail&atid=125&aid=1911&group_id=9
    BOOL properties were returning True always, small mistake in logic.c's getData method.
- #1944: http://projects.blender.org/tracker/?func=detail&atid=125&aid=1944&group_id=9
    G.vd was not being checked against NULL in Window.ViewLayer, causing a crash when this function was called from a command line script.  Now it returns an error in such cases.
- small doc updates, tiny minor change in Object.c.