CloudSigma2 ComputeService and SecurityGroupExtension

* Added the ComputeService implementation
* Added the SecurityGroup extension
* Added the San Jose region
I don't get your comment. The tested class just extends the jclouds one to avoid adding an SSH script to upload the public key. Instead of that, CloudSigma provides its own mechanism in the API to make the key populated, so there is no need to generate a statement that manually uploads it.
This test class just tests that the generated options don't contain the upload key statement when the "authorizePublicKey" option is used.