----------------
* Added threading for parallel checkouts.
[fschulze, jensens]
* Ask whether to update dirty packages during checkout.
[fschulze]
* When you answered `yes` when asked whether to update a dirty package, then
all further questions had been answered with `yes` as well, this is now
fixed.
[fschulze]
* Added `all` option when asked to update dirty packages.
[fschulze]
* Added help for all commands to PyPI description.
[fschulze]
* Added option to ``help`` command which outputs the help for all commands in
reStructuredText format.
[fschulze]
* Don't abort after user answered `no` on whether to update a package, just
skip that package.
[fschulze]