Rename llround(..) to ll_round(..) because of a collision with MS llround (long long round) in VS2013

MAINT-4415 FIXED Speak button does not become enabled after enabling voice on parcel, if voice was disabled upon parcel entry

  message

MAINT-1805 FIXED "Back" button doesn't teleport user to correct location after performing several teleports to a different locations

Agent position gets reseted frequently while not all varibles are uptadet,
as result it is not reliable for inter-region teleportation.
Changed to value from message.

replace llinfos, lldebugs, etc with new LL_INFOS(), LL_DEBUGS(), etc.

consolidated most indra-specific constants in llcommon under indra_constants.h
fixed issues with operations on mixed unit types (implicit and explicit)
made LL_INFOS() style macros variadic in order to subsume other logging methods
such as ll_infos
added optional tag output to error recorders

* Removed bogus check on matching parcel data coming in.

reviewed with Simon

Added code to start counting the fade in time on login when STATE_STARTED is set

Co-written with Robin Cornelius

* Support group members with the right powers buying land set for sale to a group
* Add dialogs for abandoned land related notifications.

Work in progress on CHOP-609 / CHOP-624 build time improvements.  Eliminated a bunch of unnecesary header dependencies.

* Now called 'HeadlessClient' instead of 'DisableRendering'
* Removed most cases where we skipped certain behaviors in the client when in this mode.  This gets us closer to a 'true' client, for testing purposes.

fixed AudioStreamingMusic and AudioStreamingMedia so they are independent
this way we can keep audio on but disable html content