Extra frame of input lag, framerate not being able to exceed 64Hz, lack of 60.1Hz and VRR support

[Skalt711]

Decided to combine all four issues into one report for the sake of simplicity.

1. I've noticed that puNES consistently adds a frame of input lag on games, which means that if the game has a frame of internal input lag, the emulator will lag by 2 frames. It happens on both D3D9 and OpenGL backends, windowed, borderless windowed and exclusive fullscreen screen modes, with and without shaders, with and without VSync, with and without VRR, which leads to the next point. MAME and Mednafen don't have the same issue, while Mesen and FCEUX do.

2. VRR doesn't work. In fullscreen I can still notice jitter of 60Hz on my 165Hz even though my screen supports VRR, FreeSync specifically. MAME and Mednafen support VRR. Dunno about FCEUX and Mesen. On high refresh rate fast forward would look smooth, but...

3. The framerate of the emulator caps at 64Hz, which means that on 165Hz screen fast forward will look like if I turned it on on 60Hz screen. Again, MAME and Mednafen don't have the same issue, but FCEUX does. Dunno about Mesen.

4. Speaking of framerates, real NES has a framerate of 60.1Hz. See here: https://forums.nesdev.org/viewtopic.php?t=492 MAME, Mednafen and FCEUX support this framerate, while Mesen doesn't.