-Cleared some traces of TextureManager
-Added AbstractLevel:
--Added support for data-driven levels
--They use json files to keep the config.
-Added still enemy as proof-of-concept.
*I'm sorry there are lots of debug lines (aka println's). Will clean
later.
Integration hell v1
Integration hell v1.1
IH v1.2
Merge branch 'master' of https://github.com/SEV-Hyperion/SpaceInvaders.git