Cannot execute workon inside a subprocess

[bouthilx]

The Runner class tries to protect trial execution from sigint and sigterm signals using signal.signal but this fails when the Runner is being executed inside a child process.

In some cases a user may need to execute the Runner in a child process. It should be possible to do so although the protection would be lost. We should warn about the sigint and sigterm instead of crashing in such situation.

[Delaunay]

Should be resolved now