pacman database queries are now handled by a singleton class into pacman module.
This will avoid a huge memory consumption to the current implementation.

Allow upstream web parsing to be retryed in case of error. The number of retry
can be set with the retry parameter.

Our error exceptions are now catched globablly and __str__ method describe
the issue

Allow to check package against local pacman synced db

Add new deps to alpm

Instead of using LooseVersion from distutils (a missed deps btw), I switched to
a custom version not directly based on tuples comparaison. Because it doesn't
support different type inside tuple.

All my package are currently passing better than with LooseVersion.

We also doesn't compute the full sorted list of versions but only the max, which
is the last.

Instead of having all tools into one arch tools repository, split into
sub autonomous project.