Update method error output to show the expression it is trying to execute.
Update method error output to show the expression it is trying to execute.

bradparks/ChaiScript__cplusplus_scripting_language,kamilzubair/ChaiScript,kamilzubair/ChaiScript,bradparks/ChaiScript__cplusplus_scripting_language,kamilzubair/ChaiScript,bradparks/ChaiScript__cplusplus_scripting_language