Rework remote targets (using ssh2) and logging

- Tidy up logging so it reads sensibly based on testing, and remove
  duplicate logging events
- Tidy up remotecontrol.js wrapper around ssh2 based on new
  understanding of the behavior of the library and be a bit more
  defensive.
- createChain and uploadFile are no longer passed from remotecontrol to
  remotetarget via callback as remotetarget wasnt using them.