softlayer_api 2.1.1

This bulk of this release will be to the documentation.  The old README will be replaced with new information about obtaining the source and building the full set of documentation.  API documentation has been supplemented with documentation on the "Foundation" and "Model" layers of the gem and I've added a Contribution Guide.

There is one bug fix in this release.  It fixes a problem that prevented the VirtualServer class from accepting any upgrades.

The target date for this release is currently Friday, June 27.