events: do not register events for self.realUnit anymore.
core: register UNIT_ENTERED_VEHICLE, UNIT_EXITED_VEHICLE and UNIT_PET as unitless to properly get the updates.
Merge pull request #203 from Adirelle/register_unit_fixes

RegisterUnitEvent tweaks
classicons: fixed ClassPowerEnable/Disable for Monk and Paladin
Merge pull request #204 from ls-/patch-2

classicons: fixed ClassPowerEnable/Disable for Monk and Paladin