Re #6096. Force completion of alg category when using class-maker.

Switch generated code from giving a category of "General" to a
comment that will not compile until something in quotes is provided.

Code/Mantid/Build/class_maker.py

@@ -132,7 +132,7 @@ def write_source(subproject, classname, filename, args):
   int %s::version() const { return 1;};
   
   /// Algorithm's category for identification. @see Algorithm::category
-  const std::string %s::category() const { return "General";}
+  const std::string %s::category() const { return TODO: FILL IN A CATEGORY;}
 
   //----------------------------------------------------------------------------------------------
   /// Sets documentation strings for this algorithm