Tweak: respond to other developer's comments

Revise TLuaInterpreter::setReplaySpeed() bar argument message to use
"number" not "float" as what is required.

Revise TLuaInterpreter::load RawFile() to now return THREE results, in
order:
* true or nil - on success or failure respectively to load and start a
  replay.
* message string - a, possibly translated, message - include upon success,
  which in that case will include the absolute path to the file loaded.
* number code - currently in range 0 to 5 with 0 corresponding to success,
  which is intended to make lua script writing easier if Mudlet becomes
  multilingual as the numbers won't change even if the message text does.

Signed-off-by: Stephen Lyons <slysven@virginmedia.com>