all: Prune trailing whitespace.

Prune trailing whitespace across the whole project (almost), done
automatically with:

    grep -IUrl --color "[[:blank:]]$" --exclude-dir=.git --exclude=*.exp |\
        xargs sed -i 's/[[:space:]]*$//'

Exceptions:
- Skip third-party code in lib/ and drivers/cc3100/
- Skip generated code in bluetooth_init_cc2564C_1.5.c
- Preserve command output whitespace in docs, eg:
  docs/esp8266/tutorial/repl.rst

Signed-off-by: Phil Howard <phil@gadgetoid.com>

ports/nrf/boards/NRF52840_MDK_USB_DONGLE/README.md

@@ -45,4 +45,4 @@ built, the target can be deployed to the device as described in
 An alternative way to deploy to the device, is to open `firmware.hex` using
 *nRF Connect* and select *Write*. Detailed instructions can be found on the
 [developer
-wiki](https://wiki.makerdiary.com/nrf52840-mdk-usb-dongle/programming/). 
+wiki](https://wiki.makerdiary.com/nrf52840-mdk-usb-dongle/programming/).