BaseClient.Send() returns structured error HTTPError

This release updates the error returned by BaseClient.Send() to use the new client.HTTPError object rather than just having Error() return the response code.

Fix template parsing

The template naming scheme isn't sensible so have to work around the
first and last split element.

Fix missing function in vm package.

Adds back missing responseOk function to vm package.

Initial release

This is an early preview release, implements a basic subset of features.