Support remote projects

[geoffxy]

INNPV should be able to support remote projects, with the help of a network mounted file system (e.g., sshfs). Most of the heavy lifting is in place, we just need to add a few more things:

• Provide a way for the user to input a "local" project root (absolute path to the mounted file system)
• Validate that the server and client "see" the same file system (exchange some kind of token by writing/reading a temporary file in the project)

[geoffxy]

We should also consider the user experience of starting one of these sessions. For example, could there be just a single command that will perform all the needed set up?

• Mount the remote project
• Start the interactive server on the remote machine
• Create a SSH tunnel

[geoffxy]

Current thinking:
Support remote projects by using a separate skyline subcommand that performs the above set up steps.

e.g.: skyline remote-interactive [entry point on remote host] [project root mount point]

Note that we need to introduce a way to modify the project root used by the plugin.