This pull request contains code changes to the already existing android code solving some of the issues. It is linked to Issue #83.

It has been minimally tested on a Google Pixel 3a but I could listen to other participants and they could hear me.

Key things are:

• Initialize the Oboe's FramesPerCallback to the proposed iNewPrefMonoBufferSize in CSound::Init()
• Only set up with a callback the input/recording stream. The output/playing stream will be written directly (non-blocking) everytime we get a callback on the input. This matches how CClient does things.
• Fixed the converstion from float to int16_t that previously resulted in the input being zero.
• Added a second vector (float) to contain the reformatted output samples. Once the default format becomes float, this could go away.

I guess there's still a lot of work to do in the handling of error cases and possible variations in the oboe behaviour across different devices, but I hope this could be a starting point.

Please comment.