Frame advancing is a commonly used TAS feature which basically means running the game frame by frame. TASers use this feature to press exact buttons at the exact frames. This commit added frame advancing to the framelimiter and two actions to the Movie menu. The default hotkey is `\` for advancing frames, and `Ctrl+A` for toggling frame advancing. The `Advance Frame` hotkey would automatically enable frame advancing if not already enabled.
Now based on std::chrono, and also works in terms of emulated time
instead of frames, so we can in the future frame-limit even when the
display is disabled, etc.
The frame limiter can also be enabled along with v-sync now, which
should be useful for those with displays running at more than 60 Hz.
