gui: First version of plot canvas
gui: plot overlay wip
gui: merge fix
Merge branch 'master' of delmic-server.local:odemis
gui: FoldPanel test case fixes
semcomedi: improve read/write cancellation

also add MMapReader version, but it doesn't work apparently due to another bug

Don't send a read cancel if the read is already done (i.e., the kernel got the fix)

Also ensure the cancel of the writer waits for the writer to be done
semcomedi: clean up

no need to cancel in the wait of the writer, the thread does it

remove debug messages
doc: add notes about crash with the comedi driver

also fix some small comments and constants
Merge branch 'master' of vpn.delmic.com:odemis