Fixes RSSI Timeout issue buy ensuring that Coffee file writes flush the SPI RXBUF after writing to the flash.
Changed timeout to be a more sensible 20s
Seems to have fixes posting issue
Merge branch 'rs485-driver2' into dec-sample-send
flash fix ported across
Conflicts:
	mountainsensing/z1-sampler/poster.c
Now more obvious is spi locking is enabled
Now default post interval makes sense given change of definition - now number of
samplea
Now doesn't sample-send but has the option
Now has posting merged in.  Commits between merge of rs485-driver2 and here are
unlikely to work on their own