Python API documentation generation tool Code

- Various formatting & css changes for the manual
- Added navbar to the bottom of generated manual html pages

- VariableDoc's containing routines with overrides != None should
return true for is_detailed()

- Added missing import statements (SF bug 1669525)

- Added :term: reST iterpreted text role to create indexed terms as X{...}
epytext markup.

- Fixed --no-frames option: frames and relative links are really not generated.
- Don't generate links for toggle_private() when --no-private option is used.

- Fixed a couple of bugs in config file parsing
- Fixed config example for fail-on option

- Some manual fixes
- Manual on the homepage.

- The manual can be created both as a single document and many pages.
The single chapters may be linked from the homepage.

- Added reST and javadoc markups to documentation
- Confug file example updated

- Check that duplicate item names are not given to build_doc_index;
if they are, then issue a warning and discard dups.
- Check that we don't generate 2 doc items with the same canonical name
from different items. This can happen, e.g., if you run
"epydoc a/x.py b/x.py" where neither a nor b are package directories,
so both modules will have canonical name "x". In this case, issue an
error message, and discard the docs from the second item.
(Otherwise, there would be 2 problems: first, we'd try to merge the
docs of these two modules; and second, we wouldn't have unique names
for them, so we'd end up overwriting the doc files of one with the
doc files of the other.)