API provides no clean way to set the --exception flag

[mpickering]

I want to always pass the --exception flag so that I can catch ShakeException and control how the output is displayed to the user. From reading the code I learned that the --exception flag exists but the only way I could find to set it was by appending --exception to the command line argument and using --with-args. It would be nicer if this option could be set by modifying ShakeOptions or something similar.

[ndmitchell]

That makes sense. Happy to take a patch - should just be a case of adding a flag shakeRaiseException and replacing the Exception alternative of Development.Shake.Internal.Args with something in ShakeOptions.