Lua5.2

--24/07/13 TWW Added code for emulating setfenv/getfenv in Lua 5.2 as per
--             http://lua-users.org/lists/lua-l/2010-06/msg00313.html
--25/07/13 TWW Copied Alex Parrill's fix for errors when tracing back across a C frame
--             (https://github.com/ColonelThirtyTwo/clidebugger, 26/01/12)
--25/07/13 DCN Allow for windows and unix file name conventions in has_breakpoint
--26/07/13 DCN Allow for \ being interpreted as an escape inside a [] pattern in 5.2