Draft installation script

This is a very-very basic installation script. It only depends on Python. It should work on Windows.

What it does:
  * detects if the console is already installed
  * downloads a gzipped tar from git
  * installs it in ~/.cocos2d/console
  * checks if the path contains the console bin directory and warns the user if not

What it also should do:
  * be able to add the console bin directory to the path?
  * ??