Ensure plugin launches when board is unplugged

[jsiegle]

See open-ephys/plugin-GUI#611

[ChucklesOnGitHub]

FYI This was happening for us in the GUI version 0.6.7, plugin version 0.2.6. I am using v0.6.6 and plugin v0.2.3 on another computer and have no issues using the OE Acquisition Board source processor in the signal chain without the board being connected.

[anjaldoshi]

Just adding to this. It is most likely happening due to a combination of the plugin and ONI/FTDI driver version. If you look at crash log attached in the original issue, the last call in the stack trace was oni_write_frame.

[jsiegle]

I was able to replicate this, and pushed a fix to the testing branch of the rhythm-oni-plugin repo. It was indeed related to checking the FTDI driver version – I just changed it so this only happens if the board is connected.