Better handling of bytes in Lua
Better handling of bytes in Lua

The Lua API for bytes was wrong up until now, and inconsistent with other
languages. It's fixed now, but the change will be incompatible with old code.
Please use Lua's `string.byte` if you still need the bytes as numbers!

Fixes #80.

lcm-proj/lcm,lcm-proj/lcm,bluesquall/lcm,bluesquall/lcm,lcm-proj/lcm,lcm-proj/lcm,lcm-proj/lcm,lcm-proj/lcm,bluesquall/lcm,bluesquall/lcm,lcm-proj/lcm,bluesquall/lcm,lcm-proj/lcm,bluesquall/lcm,bluesquall/lcm