Settings: add reset option to clock color and cleanup (1/2)

to be consistent. So we have now on all places with colorpicker
same logic + option per menu to reset color to default.

as well some cleanup and codestyle corrections

cheers

Change-Id: If4156c57420a3a72b3eb0f01cf8441ccc7bf1eeb
Signed-off-by: scotthartbti <scott@ubuntu.com>

Conflicts:
	res/values-ar/strings.xml
	res/values-cs/strings.xml
	res/values-de/strings.xml
	res/values-es/strings.xml
	res/values-fr/strings.xml
	res/values-it/strings.xml
	res/values-lt/strings.xml
	res/values-pl/strings.xml
	res/values-ru/strings.xml
	res/values-vi/strings.xml
	res/values/strings.xml