Configuration of library and creation of some classes

1. Configuration and of the library SFML (add the library of Atelier
C++)
2. Creation of classes (Entity, Tower, Projectile, Attack, AreaAttack)
Revert "Configuration of library and creation of some classes"

This reverts commit 2fde6098e758bb7335bdbbec99de415e1fc3f8eb.
Revert "Revert "Configuration of library and creation of some classes""

This reverts commit 2db9be49e8e610021caa83faf142d7fc028cbf1b.