Python API documentation generation tool Code

- Simplified code for drawing the class hierarchy; and 'object' is now
omitted from the class hierarchy.

- Removed obsolete guard against adding a class to the subclass list
twice (from introspect & parsing) -- the current implementation just
chooses the introspect's version of the subclass list over the parse
version.

- Added --inherit-from-object. Default is now to not inherit methods &
properties from object.

- Fixed bug that caused doctest blocks to sometimes omit newlines
in latex rendered output.

- Fixed bug that caused latex writer to use the wrong colorization
method for doctests containing codeblocks (not marked w/ prompts)

- Added section to the manual's reference chapter, talking about how
to customize latex/pdf output.

- Better error reporting

- Added --no-submodule-list option

- Added the latex commands \EpydocUserSection, \EpydocUserSubsection,
and \EpydocUserSubsubsection, used to add section headings inside of
docstrings.
- Added TEMPLATE to latex stylesheets

- When pre-importing modules, catch any ImportError exceptions, and
ignore them for now -- we'll report them during documentation
generation.