Report missing python packages, inform about false positives, fail
gracefully if pylint isn't installed. Fixed a bug in the ignore
list and added few more files/directories to it.
ticket 1184
This patch replaces xgettext with a custom pygettext to generate
translatable strings from plugin files in ipalib/plugins. pygettext
was modified to handle plural forms (credit goes to Jan Hendrik Goellner)
and had some bugs fixed by myself. We only use it for plugins, because
it's the only place where we need to extract docstrings for the built-in
help system.
I also had to make some changes to the way the built-in documentation
systems gets docstrings from modules for this to work.
