vim-addons: now with super completion power

Just uploaded vim-addon-manager 0.3. The best news is that it has grown bash completion powers.

After some round trips with the bug (and patch) reporter we managed to achieve a rather smart completion (e.g. vim-addons install<TAB> will complete only with the addons that you can install, excluding those which are already installed and taking into account whether or not you're asking to install a personal or system-wide addon). Cool.

PS Thanks for the patch Antonio!