Core/Movement: Port Ascent r1637 http://sourceforge.net/p/ascentemubackup/code/1637/ to TrinityCore

Port some movement packet fixes, taking into account client/server connection lag.
Credits to original author, check http://sourceforge.net/p/ascentemubackup/code/1637/ for more details.
Merge branch 'movement_fix' of github.com:jackpoz/TrinityCore