allow querying of solution data in more stages
allow querying of solution data in more stages

Previously, it was not possible to call these methods
when SCIP was stopped due to e.g. a time limit (stage: SOLVING)

SCIP-Interfaces/PySCIPOpt,mattmilten/PySCIPOpt,SCIP-Interfaces/PySCIPOpt,mattmilten/PySCIPOpt