executor: move MaRS-related code to their own file, then move SALAD to its own service
This is the first step of a long series that will ultimately allow rebooting the executor while jobs are currently running, but this change already improves the code in following ways:
- The Machine class has been split into Machine and Executor
- The MaRS class is now responsible for keeping the list of machines
- The MaRS's Machine class is now acting as a cache
The last commit converts SALAD from a library to a web service.
More work will be needed to make the Executor class a separate process.
@chturne: Thoughts on this?
Edited by Martin Roukala