[Feature Request] Create screenshots in PNG format

[sharkwouter]

Currently Play creates screenshots in BMP format, but this is not convenient when submitting compatibility reports. Github does not allow you to upload BMP image, but it does accept PNG. This means you'll have to convert it or take screenshots with a different tool if you want to add them to a Github issue.

My suggestion to remedy this would be to make Play create screenshots in PNG format.

[jpd002]

For anyone who would like to work this, would probably be relatively simple to do using libpng to save a Framework::CBitmap to a PNG.

Changing the line here would do the job: https://github.com/jpd002/Play-/blob/a86f13b3e81eebfa9185d73e4e6a3e7c6daa41b8/Source/ScreenShotUtils.cpp#L22