[MP] Port ioq3 engine based ban code.

Excludes ipv6 support for now.
New commands: rehashbans, listbans, banaddr, exceptaddr, bandel, exceptdel, and flushbans.
New CVar: sv_banFile, defaults to serverbans.dat

Needs online testing.
[MP] Fixed never fading shadow in text.
From entdark/jaMME
[SP] Fixed never fading shadow in text.
From entdark/jaMME
[MP] Add stopmusic command
[SP] Add stopmusic command
[MP] Fixed a hang in S_UpdateBackgroundTrack_Actual() when using some sample rates.

Refer to a similar commit to ioq3: https://github.com/ioquake/ioq3/commit/b9f033d1fa2a5f339654c48bcb22201d72a3de44
[SP] Fixed a hang in S_UpdateBackgroundTrack_Actual() when using some sample rates.

Refer to a similar commit to ioq3: https://github.com/ioquake/ioq3/commit/b9f033d1fa2a5f339654c48bcb22201d72a3de44
Merge pull request #582 from adnanfzafar/jedifighter

Fixed a hang in S_UpdateBackgroundTrack_Actual() when using some sample rates.
Update Changelog with some more recent stuff
[SP] Changed second declaration of S_Music_f() to declaration for S_StopMusic_f().
Merge pull request #583 from adnanfzafar/jedifighter

[SP] Corrected build error by changing second declaration of S_Music_f() to S_StopMusic_f()
[SP] Fixed external light map support
[SP] Fix for issue #580 (saber colors on saveload)
[MP] Brought over external light maps from SP
[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.