Update tools.lua - use --help flag versus -h
Update tools.lua - use --help flag versus -h

If you're using busybox, luarocks fails despite unzip being installed. Using the --help flag works in GNU, Busybox, and OSX
luarocks/luarocks,luarocks/luarocks,keplerproject/luarocks,keplerproject/luarocks,luarocks/luarocks,keplerproject/luarocks,keplerproject/luarocks