Added munit configuration to run unit test. To be used by travis.

I just did the configuration the project to be able to use munit. For now, only the basic configuration as been made. I let the ExempleTest.hx files to help the firsts tests to be implemented.

The simple following command must be run to enjoy its power :
```
haxelib install munit
```


The .gitignore file was finally added also.