Support a way to define multiple Phalcon version's stub

[cyberhck]

Right now, as soon as Phalcon releases a update, we update stubs, and older stubs are lost in phpstorm, unless we come back to this repository and download the release and install manually.

There should be a way to add multiple stubs, then user should be able to select (even better, if we could pre select by executing php commands directly, if not, user can always select)