Mute the linking sound on client kicks

This commit is really quite awesome in that you can now propagate any
plLinkToAgeMsg that will mute the link out, link in sounds, or both. Some
garbage fields were repurposed for this functionality. The messages were
passed correctly on Cyan's MOULa server.

Conflicts:

	Sources/Plasma/PubUtilLib/plMessage/plLinkToAgeMsg.h
	Sources/Plasma/PubUtilLib/plNetClient/plLinkEffectsMgr.cpp
	Sources/Plasma/PubUtilLib/plNetClient/plNetClientMgr.h
	Sources/Plasma/PubUtilLib/plNetClient/plNetLinkingMgr.cpp
Expose to python
Remove redundant bitfield
Merge pull request #281 from Hoikas/mute-sfx

Mute Link SFX