v0.4.7: smoother playback via memcpy upload + render-rate pump

- Replace per-pixel RGBA->ABGR loop in Entry.upload() with a single
  MemoryUtil.memCopy() into NativeImage's native buffer. The two layouts
  are identical when viewed as little-endian bytes, so no swap is needed.
  Cuts 1080p upload time from a ~2M-iter Java loop to one native memcpy.
- Move the frame-pump tick from 20Hz client tick (END_CLIENT_TICK) to
  per-render-frame (LevelRenderEvents.START_MAIN). At 60+fps display vs
  24fps source, this removes the worst stutter window where a decoded
  frame waited up to 50ms for the next tick. Distance-gain math stays on
  20Hz where it's plenty.
- Bump version 0.4.6 -> 0.4.7 in gradle.properties and README.

gradle.properties

@@ -5,7 +5,7 @@ org.gradle.configuration-cache=false
 
 # Mod
 mod_id=video_player
-mod_version=0.4.6
+mod_version=0.4.7
 maven_group=com.ejclaw.videoplayer
 archives_base_name=video_player