CloudSigma2 ComputeService and SecurityGroupExtension

* Added the ComputeService implementation
* Added the SecurityGroup extension
* Added the San Jose region
There has been [a recent discussion](https://github.com/jclouds/jclouds-labs-openstack/pull/135/files#r16700137) about the convenience of using the 404 fallbacks in *write* operations (typically PUT and POST). The consensus is that they should be removed, but let's address this in another pull request once this has been merged.