generate multiple lua files

idea from

https://gist.github.com/jasononeil/6458748

you can generate multiple lua files right now:

little change for LuaGenerator.hx

             #if !sharedcode
	result.add("\nfunction exec()\n");
	#end
	result.add(buf.toString());
	#if !sharedcode
	result.add("\nend\n");
	#end
	result.add(bootStr);
	#if !sharedcode
	result.add("\nexec(); exec = nil\n");
	
	result.add(starter);

example build

haxe -cp src -cp C:/Motion-Twin/haxe/lib/luaxe/git/demo -js F:/work/luaxe/luaxe- nlua/project/bin/TypeCheck.lua unityHelper.TypeCheck -lib luaxe -lib HUGS -dce full -D bootless -D unity -D sharedcode