Redesigned Welcome page using Twitter Bootstrap CSS.

Author: Tony Arcieri <tarcieri>
Signed-off-by: David-Sarah Hopwood <david-sarah@jacaranda.org>
Update helper.rst to explain new-style config. fixes #1915

Author: Zooko Wilcox-O'Hearn <zooko>
Signed-off-by: David-Sarah Hopwood <david-sarah@jacaranda.org>
Tolerate import errors when loading extra commands for "setup.py --help-commands"
and bump zetuptoolz version to 0.6c16dev4. fixes #1405

Signed-off-by: David-Sarah Hopwood <david-sarah@jacaranda.org>
Move embedded setuptools egg to reflect new version (0.6c16dev4).

Signed-off-by: David-Sarah Hopwood <david-sarah@jacaranda.org>