GenericProcessor: don't return a reference to a stack variable.

That's not gonna work. Since nullParam is just a "nothing found", put
it in static storage and return that.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

Source/Processors/GenericProcessor.cpp

@@ -54,7 +54,7 @@ Parameter& GenericProcessor::getParameterByName(String name_)
 			return p;//parameters.getReference(i);
 	} 
 
-	Parameter nullParam = Parameter("VOID", false, -1);
+	static Parameter nullParam = Parameter("VOID", false, -1);
 
 	return nullParam;