update readme to point to hardware repo #161

Job	Run time
build-arduino (release-v4.4, weather)	2m 58s
build (release-v4.4, calibration_helper)	2m 29s
build (release-v4.4, demo)	3m 15s
build (release-v4.4, dragon)	2m 33s
build (release-v4.4, grayscale_test)	3m 46s
build (release-v4.4, mpd_status)	4m 0s
build (release-v4.4, terminal)	2m 32s
build (release-v4.4, www-image)	3m 17s
build (release-v5.1, calibration_helper)	2m 26s
build (release-v5.1, demo)	4m 5s
build (release-v5.1, dragon)	3m 36s
build (release-v5.1, grayscale_test)	3m 42s
build (release-v5.1, mpd_status)	2m 35s
build (release-v5.1, terminal)	3m 15s
build (release-v5.1, www-image)	3m 19s
build (release-v5.1, screen_diag)	3m 17s
	51m 5s

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