Make support solver modules robust to inputs/outputs

Submitted by Gael Guennebaud @ggael

Assigned to Nobody

Link to original bugzilla bug (#946)

Description

See this thread for the cases of Umfpack and SuperLU:
https://forum.kde.org/viewtopic.php?f=74&t=124757

Other support modules have to be fixed too.

Blocking

#558 (closed)