Pull in changes from Lua 5.5

[Sainan]

Status: Waiting for Lua 5.5 to officially be released.

Noteworthy Changes:

• Lua 5.5 changed the 'dump' format.
  • I've added support for loading dumps from Lua 5.4, so backward-compatibility in that regard is not an issue.
• Lua 5.5 changed the format of instructions regarding 'for' loops.
  • Removed for loop optimization.
  • When loading bytecode from Lua 5.4, these instructions will cause an error.

Compatibility:

• Pluto 0.10.0 can load bytecode generated by Lua 5.4 and Pluto versions based on it, but only as long as there are no 'for' loops.
• Bytecode generated by Pluto 0.10.0 will not load on Pluto 0.9.x or below.
• Integrators should not take this compatbility for granted and try to upgrade their bytecode to Lua 5.5 when it is possible.