JCLOUDS-452: Adding bcpkix to the jclouds-sshj driver. Required by sshj.

Thanks to Andrea Turli and Ignasi Barrera for research and testing!
Adds a top-level zone filter. New live tests iterate over all available zones to ensure jclouds is fully compatible. Sometimes we want to filter to specific zones on demand.
JCLOUDS-450. Adding support for EC2 MaxCount option.

Note - no live test for this, because it's very hard to guarantee a
situation where it would be relevant.