Annotate Lua API files

[Paige Ruten]

• lua.h
• lapi.h
• lapi.c
  • initial section
  • 'basic stack manipulation' section
  • 'access functions (stack -> C)' section
  • 'push functions (C -> stack)' section
  • 'get functions (Lua -> stack)' section
  • 'set functions (stack -> Lua)' section
  • "'load' and 'call' functions" section
  • 'Garbage collection function' section
  • 'miscellaneous functions' section