added protocol27950 (2.1 PTR)

- backported support for decode_replay_attributes_events to all
protocols.
- added protocol27950 (2.1 PTR)
- NNet.Replay.Tracker.SPlayerSetupEvent is new, has m_playerId, m_type
(1=human, 2=cpu, 3=neutral, 4=hostile), m_userId (if human), m_slotId
(if human or cpu). Useful to map between users <-> players <-> slots
- NNet.Replay.Tracker.SUnitDiedEvent now identifies the killer unit:
m_killerUnitTagIndex and m_killerUnitTagRecycle
- increased resolution of tracker positions to 1x1 cells instead of 4x4
(scripts need to know the version to deal with this properly!)