Fix GMRES for complex valued problems (#35)
Fix GMRES for complex valued problems (#35)

See #34
ddemidov/amgcl,dondieselkopf/amgcl,ddemidov/amgcl,dondieselkopf/amgcl,ddemidov/amgcl,ddemidov/amgcl,dondieselkopf/amgcl