Stops drawing garbage on the screen.

Pyglet was not set to clear the window before drawing, which caused
garbage to appear on the screen.
Refactored namespaces.

Basically just moved things around so that now you import
`compgeo.d2.geo.point.Point` instead of
`compgeo.geometry.point.Point2d`.

Of course points are just an example, everything has been updated.
Fixed trailing whitespace.
Improved documentation.
Removed unnecessary imports.
PEP-8 method and attribute names.
Miscellaneous fixes, based on pylint output.