Trivial bug with Electric netlister when "ngspice" engine is chosen

[Alexandre Rusev]

Hello all!

Encountered this bg when, testing .alterparam with ngspice.

I'm not going to fix it now because it seemingly trivially fixable issue in code,

having workaround. So I'm able to port cmosedu.com examples for using of ngspice and share them with anyone

When spice engine "ngspice" selected then parameter is written quoted with single quotes to netlist '{cload}'.  Whot is incorrect syntax for ngspice

(incidented with ngspice v3.4 with Electric from repository)

In schematics:

 Capacity value is set to this string:  {cload}

In testbench

  alterparam cload=100f

Wrong string in netlist:

   Ccload gnd Vout '{cload}'

Expected string in netlist:

   Ccload gnd Vout {cload}

 WORKAROUND: choose spice engine "Spice3" and spice level: 3

Alex