Rebased fix replay

I have rebased (from current development branch) and reorganised my fixes and enhancements to the replay system, including putting some magic into the files so they can be identified more readily.  Hopefully these modifications and fixes can be adopted in their entirety, as they are interlinked - removing one step may clobber later ones...

This replaces #129 entirely and I will close that one now.
For clarification: are nil and false are treated the same? So that returning a boolean _true_ on success and _false_ (+message) on failure is also reasonable?  I would like to return:
```
{true/false} {code 0-5} {appropriate, possibly translated to users language choice, message} 
```
however you are suggesting:
```
{true/false} {appropriate, possibly translated to users language choice, message} {code 0-5}
```
I know it is not an issue right now but I am thinking ahead to the possibility of supporting more than just English and using a numeric result code could be easier for script writers  IMHO!  OTOH using a tertiary numeric code as you suggest is least likely to break existing things that already adhere to the paradigm that you say is the standard for Lua so I guess that is the way to go... expect a further commit shortly! :octocat: