Remove singleplayer directory and include some changes from halflife repository
Clean up project files
Add CHalfLifeTraining class
Add CBasePlayer::CalculatePitchBlend()
Add CBasePlayer::CalculateYawBlend()
Add CBasePlayer::StudioProcessGait()
Add CBasePlayer::StudioEstimateGait()
Add CBasePlayer::BuildRebuyStruct()
Add CBasePlayer::CanAffordArmor()
Add CBasePlayer::CanAffordDefuseKit()
Add CBasePlayer::CanAffordGrenade()
Add CBasePlayer::CanAffordPrimary()
Add CBasePlayer::CanAffordPrimaryAmmo()
Add CBasePlayer::CanAffordSecondaryAmmo()
Update CBasePlayer::CheatImpulseCommands()
Update CBasePlayer::CheckPowerups()
Mark CBasePlayer::CheckSuitUpdate()
Mark CBasePlayer::CheckTimeBasedDamage()
Mark CBasePlayer::Classify()
Add CBasePlayer::ClearAutoBuyData()