Work in progress on tonight's session

Tonight we're focusing on re-usable modules. I've extracted the grid into a Lua module and [documented it](https://github.com/CoderDojoSV/corona-game-template/blob/master/docs/grid.md). I'll be doing likewise for the character (robot, runner, kitten), obstacle (static image-backed objects on grids from rfk), as well as creating simple controlpad and button modules.

The modules will be delivered to students in a game template directory with the source code and text-based documentation for each module. The template project will remain available indefinitely for any new games the students wish to use it for after the course is over.

Before we're ready for tonight we need

- [x] grid module completed
- [x] grid module documented
- [x] character module completed
- [x] character module documented
- [x] controlpad module completed
- [x] controlpad module documented
- [x] Examples for grid module
- [x] Examples for character module
- [x] Examples for controlpad module

I'm particularly interested in examples that go beyond what we've used these libraries for in the past and ones that kids could use in making their explorer game.