Standardize stream frame format and interface

[jhugon]

• [x] Standardize stream frame counter to be 0-255
• [x] Implement send_stream message in python
• [x] Above for C
• [x] Implement stream receivers in python
• [x] Update tests

[jhugon]

I'm removing implement stream receivers in C from the task list. This doesn't seem like the time for that.