Pin names like "+V" were incorrectly parsed as doubles leading to broken
comparisons. These caused heap overflows when sorting pin tables
This corrects the comparison so that numeric sorts are only performed
when there is an actual number in the symbol segment. Also adds unit
tests for common error cases
SIMULATOR has now an Attach() method, which should be called
with proper SIMULATION_MODEL that should be simulated, before calling Run()
Concrete class of SIMULATION_MODEL for ngspice is NGSPICE_CIRCUIT_MODEL,
renamed from NETLIST_EXPORTER_PSPICE_SIM. DIALOG_SIM_SETTINGS relies
on above mentioned object, so it was added as an argument of the constructor.
Seth Hillbrand
Roberto Fernandez Bautista
Sylwester Kocjan