microRTPS: fix UART link

[TSC21]

Currently the microRTPS bridge UART link is broken and it's resulting on continuous CRC errors on the agent side that after some seconds close the link. This is being investigated.

Also, it was verified that a stack increase was required to avoid the micrortps_client of causing and hardfault and rebooting the flight controller.

[TSC21]

@AndrewWedemier thanks for your insights and your debugging effort, which ended-up helping me unblock this! Added you as a co-author in one commit, which was the commit that allows to have the bridge usable over UART.

Note that for setups which are to run at baud rates <=1MByte/sec, it's required to throttle the overall publishing using the -w option. So with the current default streams (per 07/20/2020), something like:

micrortps_client start -d /dev/ttyS2 -b 1000000 -v -w 6
./micrortps_agent -d /dev/ttyUSB0 -b 1000000 -v -w 6

works nice without any errors, though it introduces some latency on the link. The alternative is also increasing the baud rate. Found that using 1.5MByte/s with the current default streams is enough to have it work properly.

micrortps_client start -d /dev/ttyS2 -b 1500000 -v
./micrortps_agent -d /dev/ttyUSB0 -b 1500000 -v

Note that with the increase of the number of topics being streamed, and depending on each rates, this might change and might require changes on the stream rates.

[bkueng]

Much better, thanks.
Can you also cleanup the commits? There should not be revert commits.

[TSC21]

Thanks @bkueng!