[JCLOUDS-702] JCloud ProfitBricks provider implementation

Hi! This implements most of ProfitBrick's API. I look forward for your comments, suggestions, and revisions.
Hmm. I still don't get this. By property do you mean like in <a href="https://github.com/devcsrj/jclouds-labs/blob/master/profitbricks-c2/src/main/java/org/jclouds/profitbricks/ProfitBricksApiMetadata.java#L59-L60"><code>ProfitBricksApiMetadata</code></a>? Or  the one in <a href="https://github.com/devcsrj/jclouds-labs/blob/master/profitbricks-c2/pom.xml#L51-L52">POM</a>? (The above follows the one in <a href="https://github.com/jclouds/jclouds-labs/blob/master/digitalocean/src/main/java/org/jclouds/digitalocean/compute/strategy/DigitalOceanComputeServiceAdapter.java#L102-L103">Digital Ocean</a>)