readme: lossy should now work in Safari

As of at least WebKit/605.1.15 createImageBitmap is
also supported in WebKit based browsers like Safari.
Testing with WebKitGTK 2.34.4 confirms that our brotli-compressed
sample using the lossy rendering mode plays fine.

Author: TheOneric

README.md

@@ -157,7 +157,7 @@ thread, instead will run Async, so if the function createImageBitmap fail, it
 will not stop the rendering process at all and may cause some bitmap loss or
 simply will not draw anything in canvas, mostly on low end devices.
 
-**WARNING: Experimental, not stable and not working in Safari**
+**WARNING: Experimental, not stable and not working in some browsers**
 
 
 ### Brotli Compressed Subtitles