Fix errors introduced by new config format

[ma595]

This PR fixes the execution of SPINacc as errors were accidentally merged from #52:

• DEF_Trunk path was hardcoded. Now passing a different directory on the command line actually works.
• The results directory was not created if it didn't exist
• Previously the tasks were skipped (as none of the tasks checks passed) as the list of tasks is instantiated as type integer in config.py.