This patch adds a getUint8 getter for ByteBuffers and changes ApfFilter to make uses of getUint8/16/32 everywhere. The return types of getUint16 is also changed from long to int, which will expand gracefully to long as an unsigned int as it is guaranteed to be positive after getUint16. Test: ApfTest passes Change-Id: Id3c2817b949e9817e2bb60e0ec8fe2d6fd8d787c