9.7.0-beta-7

Changes from 9.7.0-beta-6:

• Switched to the CMake building system (CLion, Visual Studio and more now be used to develop/build this module)
• Completely restructured the code
  • Mysql and Lua classes are now separated
  • Lua is now fully in charge of the lifetime of Userdata/Lua objects
• Severely improved garbage collection performance
  • You can now create thousands of queries in one go without any lag
• Improved performance when launching the same prepared query many times in a row
• Added integration test of (almost) all functionality in Lua, including basic memory leak checks
• Fixed several bugs, including some possible heap corruption on map change
• Fixed a memory leak that could lead to out of memory errors after running for a long time