Payload for interval requires update in design document and code

[mofosyne]

Design Doc should be updated

Main change is that instance ID is added

[
 Object ID,
 Instance ID,
   [
   [BLOCK0],
   [BLOCK1],
   ...
   ]
]

Where a block should have

[
 Interval Start Timestamp,
 Interval Period,
   [
   [SAMPLE0],
   [SAMPLE1],
   [SAMPLE2],
   ...
   ]
]

[mofosyne]

Readme updated. And code updated. 991b105