Adapt to repository migration

- Change https://github.com/tarruda/libmpack references to
  https://github.com/libmpack/libmpack.
- Remove lua binding, which is now at https://github.com/libmpack/libmpack-lua.

[lua] Bump

[lua] Bump

[lua] Bump

[lua] Bump

Add travis build for lua binding

Also add a Makefile to simplify setup