Migrated zeitgeist-sharp from ndesk-dbus to dbus-sharp.
* Removed ndsk-dbus as dependency and added dbus-sharp as dependency * Made a check for zeitgeist >= 0.7.1 in configure.ac. Has to be moved to >= 0.8.0 before release * Removed System.Core as reference in Zeitgeist.csproj * Removed the weakly-named System assembly reference and added strongly named System assembly reference