Allow kernel build to be specified from command line.

This change fixes a few glitches and adds functionality that:
- allow kernel builds to be explicitly specified via parameters,
- allow forced updates of image files,
- include socat in cuttlefish dependencies
- verbosely list transferred files.

Change-Id: I7b05d8f30eed9891c8b18e603c7cf29418c1a395
(cherry picked from commit d3e6aa7a449020f015f075d5966d8c2392d5f538)
3 files changed