Replay fixes

[NQNStudios]

A round of replay system fixes and improvements.

• replaying the debug help window was broken in 2 ways which I fixed
• Fix Record replays in memory #559 -- When we observe bugs in random sessions, we no longer have to regret that we didn't pass --record at the command line. The replay data is kept in memory and writing it out can be enabled with debug action Z.
• Recording replays into the working directory by default is pretty wonky, because the working directory is usually a build output folder that might be clobbered by a scons -c, wiping out important replays. Also, if the working directory is the Visual Studio project folder, you end up adding untracked files to your repo folder which can get annoying. So - I've made the default replay directory a folder alongside the tempDir that already exists. On Windows, this is in AppData, on Mac it's in Application Support, etc. But if you pass an explicitly relative or absolute path, it is resolved as expected.
• I made a mistake a while ago that made the Debug action N (end scenario) not get recorded. Fixed!

[NQNStudios]

I'm rounding up a bunch of these fixes as I've finally made a replay that contains (almost) all of the debug actions. More to come.

[NQNStudios]

With those last two, the whole replay runs correctly.