Baked the CRC class into TokenStream

One less file! :)
Removed run.bas in favour of a simple form, so that events can be sunk from the Assembler object

* Error events improved and a Message event added so as to do away with internal Debug.Print use
* Removed string storage from the TokenStream object

- The Assembler will pool together the strings from all TokenStream objects (one per source file). This is done via an event fired by the TokenStream object to pass the string up to the assembler
* Split the Oz80 disassembly into some separate files and improved use of OZ80 syntax in some areas