Adding custom Commands in zf2

It was not possible to add commands to doctrine-Cli commands list using onBootstrap method.
So in order to add our custom commands we need to use init method of Module class.

Second of all $cli object does not have addCommand method but it does have "add" for adding one command at a time.
Merge pull request #462 from baghayi/patch-1

Adding custom Doctrine-Cli Commands