Erasing enviroment.Content and enviroment.Abstractor
Adding Exception throwing to some loaders
Passing modulename as args
Stop using content on level.js
image is no more inherited from enviroment.Content and now its loading logic is now on image_loader()
Fixing iss4 and part of iss3

-Automatically passing name args if modulename is present
-Removing map.js and adding plain_map.js and isometric_map.js
-Checking arguments on loaders and throwing exceptions when not enough args
-Heavy refactoring tilemap.js
-Adding orthografic_camera.js
-Adding some newlines at end of files
-async_download is accesible at enviroment.async_download
-level/flatland.json works!!
-map format changed a little bit
Fix #4
Fix arg name on skyline.json