Bit-library file removed from the project (as it was deprecated)

This commit only removed the file 'lbitlib.c' from the project; the
makefile already was not using it.

lbitlib.c

@@ -1,7 +0,0 @@
-/*
-** $Id: lbitlib.c,v 1.31 2017/11/16 13:19:06 roberto Exp roberto $
-** Standard library for bitwise operations
-** See Copyright Notice in lua.h
-*/
-
-Deprecated module.