Make changes:
1. Set bFirst and bFindPPS to true when it comes to I Frame to make
application more stable;
2. Fix the probe_sps function not work when h264 bit stream contains
more than one SPS;
3. libH264Decoder.so change, fix the problem that Java layer can not get
the realWidth and realHeight value for the unexpected return -1
***small change in order to fix the black and while video screen while
exhchanging channel, but it seems not work