WIP azure: finalize azure image

The VHDs uploaded into azure must be sized a multiple of 1MB and the kernel
needs some custom boot parameters.

I still need to figure out dynamically sized images. Otherwise, we'll be pushing 8GiB over the network...
And:

```python
  def Align(count, alignment):
    offset = count % alignment
    if offset:
      count += alignment - offset
    return count
```