[Core] Beginning to implement dungeon proposals in the Dungeon Finder.
[Core] More work done to proposal system for Dungeon Finder
[Core] Proposal work for Dungeon Finder, barring some testing is
essentially complete. Teleporting players after a proposal should now be
possible.
[Core] Added hooks in achievement system for dungeon finder rewards.
*Note: This should be applied to mangos three & four as well

[Build] Fixed some build errors in dungeon finder and g3dlite.
*Note: Fixed in g3d should be applied to all cores, it's a minor fix for
clang and shouldn't affect anyone else.
[Core] Use ObjectGuid instead of its raw value for dungeon finder.
Will make work easier, cleaner, and it will make the job of porting this
to other mangos cores easier as the raw value type may not stay
constant.
[Core] Implement Dungeon Finder rewards system and SMSG_LFG_PLAYER_REWARD
[Core] Begin to incorporate hooks/changes to implement the boot system
in the Dungeon Finder
[Core] Implemented boot system for the Dungeon Finder
* The outward functions of the dungeon finder should work now
* There still needs to be testing to make sure it works, however.
* There is also a good amount of internal work to be done.
[Core] Small typo in LFGHandler
Merge remote-tracking branch 'upstream/Rel19' into Rel19