Added support for Lua DBGp Debugging such as Eclipse debugging

To support this CorsixTH simply needs to have "debugger.lua" and a
"dofile('debugger')()" call to it.

This Lua script was created by Sierra Wireless and others & cannot
be legally distributed with CorsixTH so developers must download it
& place it in their Lua directory in order to setup CorsixTH for
Lua DBGp debugging.

I've made a new function for the call "dofile('debugger')()":
App:connectDebugger().

I've created a new main menu button to call connectDebugger() when
config.debug = true and I've also added a connectDebugger()
command to the debug menu.