CloudSigma2 ComputeService and SecurityGroupExtension

* Added the ComputeService implementation
* Added the SecurityGroup extension
* Added the San Jose region
@demobox If I make them protected they become invisible to tests. E.g. I get the following error in `ServerInfoToNodeMetadataTest.java`:

    jclouds-labs/cloudsigma2/src/test/java/org/jclouds/cloudsigma2/compute/functions/ServerInfoToNodeMetadataTest.java:[60,1] cannot find symbol
    [ERROR] symbol:   static serverStatusToNodeStatus
    [ERROR] location: class
    ...
    jclouds-labs/cloudsigma2/src/test/java/org/jclouds/cloudsigma2/compute/functions/ServerInfoToNodeMetadataTest.java:[170,13] cannot find symbol
    [ERROR] symbol:   variable serverStatusToNodeStatus
    [ERROR] location: class org.jclouds.cloudsigma2.compute.functions.ServerInfoToNodeMetadataTest