The frame number is incremented before the first frame is swapped out.
Fixes ffmpeg creating invalid video files on output if the emulator only
runs for a single frame, e.g. FifoCI.
Migrates most of VideoCommon over to using fmt, with the exception being
the shader generator code. The shader generators are quite large and
have more corner cases to deal with in terms of conversion (shaders have
braces in them, so we need to make sure to escape them).
Because of the large amount of code that would need to be converted, the
conversion of VideoCommon will be in two parts:
- This change (which converts over the general case string formatting),
- A follow up change that will specifically deal with converting over
the shader generators.
