failure when using config and a current probe as output

[Bart Moeneclaey]

Skill code for traversing config in order to get spectre pin name mapping is not implemented.

Execution fails when using config and a current probe as output.

A workaround is presented in branch fix/output_probe_config, commit #427ec95: If a config is used, assume pin name mapping is ":p".

[Bart Moeneclaey]

workaround is merged with master in commit a10f02d