docs: re-enable missing manpage

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Import command not module

This matches the function name
config: add decorator to add_option_* functions

This allows us to build an internal list of valid options and print
these.
Document changes and release 0.6.13
Slightly improve usage output
gbp pq: document --force
Handle version format errors more gracefully

So far if a package claimed to be non native but the version number
didn't contain a '-' we failed like:

  Traceback (most recent call last):
    File "/usr/bin/gbp", line 9, in <module>
      load_entry_point('gbp==0.6.13', 'console_scripts', 'gbp')()
    File "/usr/lib/python2.7/dist-packages/gbp/scripts/supercommand.py", line 82, in supercommand
      return module.main(args)
    File "/usr/lib/python2.7/dist-packages/gbp/scripts/buildpackage.py", line 541, in main
      output_dir)
    File "/usr/lib/python2.7/dist-packages/gbp/scripts/buildpackage.py", line 96, in prepare_upstream_tarball
      upstream_tree = git_archive_build_orig(repo, cp, output_dir, options)
    File "/usr/lib/python2.7/dist-packages/gbp/scripts/buildpackage.py", line 270, in git_archive_build_orig
      upstream_tree = get_upstream_tree(repo, cp, options)
    File "/usr/lib/python2.7/dist-packages/gbp/scripts/buildpackage.py", line 245, in get_upstream_tree
      cp['Upstream-Version'])
    File "/usr/lib/python2.7/dist-packages/gbp/deb/git.py", line 107, in version_to_tag
      return format % dict(version=DebianGitRepository._sanitize_version(version))
    File "/usr/lib/python2.7/dist-packages/gbp/deb/git.py", line 122, in _sanitize_version
      return version.replace('~', '_').replace(':', '%')

It shouldn't be like that.
Fix comitter vs committer typos

Thanks: Sandro Tosi
Closes: #748339
Documnt that the patches must apply without fuzz
pq: Print proper error message if we fail to apply the tree

e.g. instead of

gbp:error: Failed to apply 'debian/patches/poison+remember_trash'

we now have

gbp:error: Failed to apply 'debian/patches/poison+remember_trash': Failed to commit tree: fatal: invalid date format: 1998/03/21
pq: Try harder to cleanup after a failed patch

If we fail to apply the patch the tree is left in a dirty state
so reset to the last head. This avoids irritating errors like:

gbp:error: Failed to apply 'debian/patches/poison+remember_trash': Failed to commit tree: fatal: invalid date format: 1998/03/21

following files would be overwritten by checkout:
	doc/hosts.nntp.5
	innd/art.c
	innd/innd.h
	innd/rc.c
Please, commit your changes or stash them before you can switch branches.
Aborting

Thanks: Marco d'Itri for the repo to debug this
Determine build_dir upfront

so it's available to all hooks
Improve error reporting on failed commands

Make it more clear if the command exited with non zero exit status.
Also don't report the command line twice.

Closes: #748248
Improve error reporting on hooks

Make it obvious that a hook failed and not a gbp internal function
Document changes and release 0.6.14
Revert "Determine build_dir upfront"

This reverts commit b2549fac19f2d666552291a4fcf2020ca0570834.
Document changes and release 0.6.15