Implement purple.Buddy()

Implemented Buddy class and some basic methods. Python application using python-purple, now can has a buddy dictionary in format: buddies = {<buddy.name>: Buddy()}

TODO: Link Buddy() and Account(), maybe using account->ui_data.

Signed-off-by: Anderson Briglia <anderson.briglia@indt.org.br>

git-svn-id: https://garage.maemo.org/svn/carman/branches/carman-0.7-beta2/python-purple@1348 596f6dd7-e928-0410-a184-9e12fd12cf7e