Add bonecp example to connection pooling recipe

In the past few years c3p0 has been a quite stagnant project, while BoneCP has arisen as a good alternative, much faster (see f.i. http://jolbox.com/index.html?page=http://jolbox.com/benchmarks.html), and equally reliable. 

I think it would be useful to add the code samples to use BoneCP to this recipe, since they are very similar (see pull request)