[MP] Fix snow entity wind vector whitespace.
Updated more stuff to changelog
[SP] Fix #563 - bad swoop explosion rendering

As mentioned in the issue, the problem first appeared in 21c03df. I had
assumed the last argument was the same as in MP's G_PlayEffectID, but
SP's G_PlayEffect function wants a forward vector, not Euler angles.

Changing this to be a direction vector of (0, 1, 0) fixes the issue.
[MP] Fix incorrect memset sizeof
[SP] Add support for mousewheel down to ITEM_TYPE_MULTI which doesn't have a cvar attached.
[MP] Unused CG_ZoomDown_f and CG_ZoomUp_f
[MP] Remove redundant sound is muted message in soundinfo.
[SP] Remove redundant sound is muted message in soundinfo.
[MP] Fix bots being afraid of [detpacks/tripmines/thermals] which belong to them or their teammates.