mdb runner/parser WIP

Do I continue like this? or just integrate the mdb runner itself into
luadebug?

runners/shell.lua

@@ -25,6 +25,8 @@ function shell:run(target, name)
     self.error(string.format("command not specified for target %s", name))
   end
 
+  self.on_state('running')
+
   -- output pump
   core.add_thread(function()
     while true do