Made story title prefix customisable.

[mwhelan]

Implements #68. Allows you to customise the story title prefix for all reports by setting TitlePrefix property in the Story attribute. Defaults to current behaviour of "Story: "
Implements #95. Added RunDate to FileReportModel and removed date funcs.

[MehdiK]

Why not default titlePrefix to "Story: " here?

[mwhelan]

I did initially do that. However, I realised that when the other constructor was called, it passes in narrative.TitlePrefix to that parameter and would override that default value. I would expect narrative.TitlePrefix to often be null. That would mean I would need to set a default for that constructor too:

narrative.TitlePrefix ?? "Story: "

which means I'm effectively setting the default twice. Doing it in the constructor means I only have to set the default value once. And it's kinda consistent with how Title is being set.

[MehdiK]

Cool. Thanks :)

[MehdiK]

This is a small but very useful improvement. I like it :)

There is only one small nitpicking that would be good if you could fix. Will merge then.