Added an initial implementation of a vSphere provider.
Retooled volume management to work with both EC2 and vSphere.
Force delete volumes when deleting vSphere instances.
Use our local IP configuration for describing instances since the remote configuration may not be 100% initialized yet.
Handle code updates in case the deploy directory or an ancestor root was remounted.
Disable password-based SSH login vSphere after the SSH key has been uploaded.

Also allow configuration of an initial SSH password.

Disabling password-based SSH is far more secure, especially when using a static, base password.  On the off-chance this screws up, the user should always be able to log into a console session from vCenter.
Allow configuring memory and CPU count for vSphere VMs.
Updated configuration references.
Don't blow up if :initial_ssh_password isn't set.
Cleaned some code up.
Rubber can now create and provision multiple NICs on vSphere.
Allow cloud-level IP settings configuration to avoid duplication in the host configs.
Added more vSphere IP configuration validation.
Allow deleting a cloud-level configured gateway by setting the host-level value to null.
Merge pull request #414 from rubber/vsphere_support

Added vSphere support.