Core/Log: Allow configuring a maximum file size for a log file. If the file size is about to be exceeded, the core will create a new file titled <oldname>_.log and start outputting there.
Core/DBLayer: Drop support for MySQL versions <5.1

Both server and client libraries must be up to date in order to run TC.
Scripts/Icecrown Citadel: Fixed Essence of the Blood Queen interrupting player spell casts

Closes #8665
Tools: Remove a bit of spam when mmaps_generator loads vmaps
Merge branch 'HEAD' of git@github.com:TrinityCore/TrinityCore.git
Tools/mmaps_generator: Multithreading optimisations. Should save some time generating mmaps.
Fix magic numbers