Implemented the ability for the user to add new input types

[snibo]

As the title sais now you can make it so any function that can output a number between 0 and 1 to be it's own input type and can be used along side the other ones. For more details on how to use it check the bottom of the updated readme.md

This feature is useful for UI and especially for mobile games since it allows you to easily bind the touch controls using baton.