Removes attempts to register the speex JavaEncoder and JavaDecorer classes, since they are exluded in the default libjitsi build, and trying to register them raises exceptions.

Commits work in progress on utilizing Android's native hardware (and software) decoding (and encoding) via MediaCodec.

Fixes a problem with the VP8 Packetizer sometimes not sending the last chunk of a packet correctly. Changes the VP8 encoder and decoder used to the ones based on libvpx. Updates libjitsi.jar

Adds support to encode and decode VP8. Note that a vp8 encoder and decoder need to be build into the jnffmpeg library in order for this to work, and prebuild binaries aren't ready yet.