Core/Movement

* Implemented a generic way of sending movement packets depending on who controls the unit (player or server controlled)
* Added possibility to specify extra elements in movement packets (such as speed, extra passenger guid, collision height and similar) without having to add a special element only for these
* Removed Unit::SendMovementFlagUpdate as it was something working only in 3.3.5a and earlier (no serverside HEARTBEAT opcode exists now)
Core/Players: Minor cleanup in PhaseMgr
Core/Objects

* Vehicles can now be sent with UPDATETYPE_CREATE_OBJECT2
* Corrected HIGHGUID type for guilds