[mr3155] Fix Arena problem. close #1429
[mr3156] Improvement group system.
[mr3157] Happy new year guys! good holidays for you! =)
[12580] Improve chat channel code:

- Remove unnecessary calls to GetPlayer
- Invert "if" statements to reduce nesting
- Cleanup code

Signed-off-by: stfx <stfx@hotmail.de>

Conflicts:
	src/game/Channel.cpp
	src/shared/revision_nr.h
[12581] Implement 2 chat channel responses

- CHAT_PLAYER_NOT_BANNED_NOTICE
- CHAT_PLAYER_INVITE_BANNED_NOTICE

Signed-off-by: stfx <stfx@hotmail.de>
pick from 12583 - Add a configurable delay between when a creature respawns and when it can aggro due to movement (only for compartibility! check config please)
[12584] Rename m_respawnAggroDelay to make it more generic
[12586] Fixed issue with PCH not working on some versions of GCC

Since some versions of GCC doesn't output patchlevel on -dumpversion the PCH check can fail.
Bug: https://github.com/cmangos/issues/issues/81
[12587] Chat system refactoring All chat function now call same method

I also reworked the packet structure to be more near of original.
Due to havy of code changed this commit need to be applyed carrefully.

Any feedback is welcome here or on cmangos.net
[12590] Add BuildChatPacket comment, reorder parameters, correct a little bug gm name not showed on general channel (Thank to @Shauren for pointing).
[mr3158] fix old methods after chat rework
SD2 update
Merge branch 'master' into testing
remove double update time resetting (from mr3125), thx to Undergarun && mns. related to #1433
fix one GM crush after 12587