Use new PRNG and implement entropy gathering and seeding This patch updates the zrtp4j and the lightweight crypto libraries. Both libraries implement and use the Fortuna PRNG that create high quality random data. The new GatherEntropy class implements methods to gather random data from media capture devices and use this data as entropy to seed the Fortuna PRNG. This enhance the quality of random data. This works with portaudio, JMF audio not yet supported, video may be added at a later time.