README: updates.

- GStreamer 1.2 APIs are supported ;
- Video Processing (VA/VPP) features.

README

@@ -46,6 +46,10 @@ Features
   * Support for the Wayland display server
   * Support for headless decode pipelines with VA/DRM
   * Support for major HW video decoding solutions on Linux (AMD, Intel, NVIDIA)
+  * Support for VA Video Processing APIs (VA/VPP)
+    - Scaling and color conversion
+    - Image enhancement filters: Sharpening, Noise Reduction
+    - Advanced deinterlacing: Motion-Adaptive, Motion-Compensated
 
 
 Requirements
@@ -61,7 +65,7 @@ Software requirements
       libgstreamer-plugins-bad0.10-dev (>= 0.10.22.1)
         or with GstVideoContext, GstSurfaceBuffer, codecparsers
 
-  * GStreamer 1.0.x:
+  * GStreamer 1.0.x (including GStreamer 1.2):
       libglib2.0-dev (>= 2.28)
       libgstreamer1.0-dev (>= 1.0.0)
       libgstreamer-plugins-base1.0-dev (>= 1.0.0)