* Move GCC to GCC 6 & GCC 7
* Move Clang to Clang 3.6 & Clang 4.0
* LINT moves from Clang 3.9 to Clang 4.0
* Move XCode 7.3 to 8.0
* Use more travis tricks to install compilers instead of adding complexity to our build script
* Clang format fixes on checked files (compat Cpp11 instead of Cpp03)
* Mingw GCC update from 4.8.4 to 5.3 (Ubuntu Xenial)
* Drop mingw cmake generated files and add them to gitignore
* Player data to Database
Add player data into databases (SQLite3 & PG only)
PostgreSQL & SQLite: better POO Design for databases
Add --migrate-players argument to server + deprecation warning
* Remove players directory if empty
* Remove the copy from db::loadBlock by using a pointer to the destination
* cleanup db backend, the child backend doesn't have to set their functions as virtual
