ReadFromBs: fix for Lua >= 5.2 (unpack)
ReadFromBs: fix for Lua >= 5.2 (unpack)

https://travis-ci.org/npge/lua-npge/jobs/91505883#L2354

npge/lua-npge,starius/lua-npge,npge/lua-npge,starius/lua-npge,npge/lua-npge,starius/lua-npge