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.
They're not presented to the user in the standard file dialog in any particular order if I remember correctly so why bother with that?  And I came across this issue with a collection of map saves that I had copied from one place to another to free up some space, it was only when I came to put them back I found the date- time info has not been preserved and it was a pain picking through a few screenful to pick the ones I wanted to save because of their date .  My point is why not KISS it to start with.  Besides the previous choice might seem more confusing in the USA who use: mm-dd-yyyy whereas this choice does have logic behind it. :smile: