[Improvement] show version number of PresentMon somewhere in the UI

[da-anda]

I was surprised to see that there is no way to see which version of PresentMon is installed on the system unless you check the list of installed software in Windows. It was super weird to see that there is no "about" page in the settings and that the version number is nowhere to be seen anywhere in the UI.

I know that an about page (along with maybe a "check for update" button 🤞) will likely be a bit more work, so my suggestion would be to at least show the version number (or GIT rev in the case of nightlies/custom builds) in either the window title bar next to the application name, or (maybe better) in the blue footer bar that currently displays some refreshrate info (or whatever that should be)

Thank you.