Dev

Implemented following:

1. Support for internal load balancer
2. Disk host caching while attaching disk
3. Support for regionwise VNet
4. Bug fix: unable to create affinity group as a part of vnet creation

Rephrase error message to something like the following:

> Another image of type "%s" exists with the same name. Image capture is being aborted to avoid duplicates and potential conflicts. Please use another name for the image.