Fixes a crash introduced with the mentioned revision, since one can only
have a single instance of the ne7ssh object. Poroper fix follows next.

Reviewed-by: ck

Since the ne7ssh implementation starts the select thread directly inside
the constructor, we would have it polling after initializing the project
manager. Still we should apply the fix Thiago proposed for polling.

Reviewed-by: ck

Currently deactivated via #ifdef, but has been tested successfully.

The code is #ifdef'ed out for now, but has been successfully tested.

We now have two subclasses for deploying files and
running commands, respectively.

This will replace the current ssh-via-QProcess approach, which
has severe drawbacks.