Context.py event attribute fixes

[Andrene]

Should fix issue #176

[cclauss]

Why not UnitDiedEvent.killing_player_id as mentioned in CHANGELOG.rst?

[Andrene]

The changes I made were to handleUnitPositionsEvent and handleUnitDoneEvent, neither of the associated events processed by those have either attribute. In the above commit I fixed the reference here

sc2reader/sc2reader/engine/plugins/context.py

Line 201 in c17bd35

event.killer_pid, Length(seconds=event.second), event.frame

I dont think that killing_player_id or killer_pid would be a good fit there, as the error that is logged references being unable to delete a unit index, and the if condition above checks if the unit_id_index is in the list of active units, so to me it'd make sense to use the unit_id_index

Further down in the handleUnitDiedEvent function an error for unknown killing player id exists and uses the appropriate non-deprecated attribute

sc2reader/sc2reader/engine/plugins/context.py

Line 219 in c17bd35

event.killing_player_id, Length(seconds=event.second), event.frame

[StoicLoofah]

Looks good, thanks!