Simulation bug fixes.

1) Use C-locale when converting output of parsers to strings.

2) InferSimModel() must run on local copy of fields, not the fields in
the symbol (which might be different if they've already been edited in
the Symbol Properties Dialog, for instance).

3) InferSimModel() should accept a deviceType already set to RLC.

4) Don't output trailing decimal separators if there's no fraction.

eeschema/sim/sim_value.cpp

@@ -509,6 +509,8 @@ bool SIM_VALUE_FLOAT::FromString( const std::string& aString, NOTATION aNotation
 
     try
     {
+        LOCALE_IO toggle;
+
         m_value = std::stod( parseResult.significand ) * std::pow( 10, exponent );
     }
     catch( const std::invalid_argument& )