updated reference to rpi_ws281x sub module to point to penfold42 fork (#655)

* Removed -HUP so the default -TERM signal is sent instead.
- hyperiond only listens for TERM and INT. HUP is often used to get an exe to reread its config

Changed pgrep to add '-x' so it wont partial match on the exe name.
- I have multiple instances with multiple hyperiond-instance1 names
- this ensures the service script only kills the right process

* reversing errant change to hyperion.systemd.sh

* cleaned up a couple of compiler warnings

* moved bitpair_to_byte initialiser to (hopefully) work with older GCC

* compiler warning in udp driver
removed some tabs in ws2812b.cpp

* formatting - spaces to tabs

* moved rpi_281x to tag sk6812-v1.0

* moving to my fork of rpi_281x


Former-commit-id: 34ca0f4f760c6cbb47d3c434c920827ce12bb23e

.gitmodules

@@ -3,4 +3,4 @@
 	url = https://github.com/tvdzwan/protobuf.git
 [submodule "dependencies/external/rpi_ws281x"]
 	path = dependencies/external/rpi_ws281x
-	url = https://github.com/jgarff/rpi_ws281x
+	url = https://github.com/penfold42/rpi_ws281x