having trouble restoring transformed TURN commands

The solution to this problem turned out to be easy: there was a latent bug in ```contrib/build_dfas.py``` which resulted in malformed DFAs in ```regex2dfa.js```. I simply regenerated ```regex2dfa.js``` and this solved the issue.

However, implementing a unit test that verified this fix (see: ```src/fte_transformer_test.js: fte_issue12_test ```) turned out to be cumbersome. This required a major refactor. The end result: I've added a ```make test``` target which runs a test script for rabbit and a test script for fte under node.js. This refactor means that, in future, it will be a lot easier to add unit tests. Sample output:

```
$ emconfigure ./configure
...
$ make
...
$ make test
SUCCESS	fte_basic_test
SUCCESS	fte_issue12_test
SUCCESS	rabbit_basic_test
```
I think it would be very helpful to mention that these bytes are a STUN message.