Move builtin wholesale to Mom

Since Builtin generates risc, just like mom instructions, it was a design mistake to put builtin into risc in the first place. Now that borders are coming more into focus, it make much more sense to have the builtin in mom.
In fact the instructions should be moved out and a seperate invocation mechanism used , so functions can be parsed, not generated (wip)

lib/risc.rb

@@ -12,15 +12,11 @@ class Class
   end
 end
 
-# The Risc Machine, is an abstract machine with registers. Think of it as an arm machine with
-# normal instruction names. It is not however an abstraction of existing hardware, but only
-# of that subset that we need.
 # See risc/Readme
 module Risc
   # module method to reset, and init
   def self.boot!
     Position.clear_positions
-    Builtin.boot_functions
   end
 end
 
@@ -47,5 +43,4 @@ end
 require_relative "risc/instruction"
 require_relative "risc/register_value"
 require_relative "risc/text_writer"
-require_relative "risc/builtin"
 require_relative "risc/builder"