Added relevant constants from DateUtils
Added relevant constants from DateUtils

I did not add all of the constants from Android's DateUtils.  Some of them are
unnecessary when combined with Joda-Time and others have been deprecated long
ago.

ptornhult/joda-time-android,xfumihiro/joda-time-android,xfumihiro/joda-time-android,netfirms/joda-time-android,dlew/joda-time-android,lucasxas/joda-time-android,dlew/joda-time-android,andyao/joda-time-android,rjhonsl/joda-time-android,rjhonsl/joda-time-android,netfirms/joda-time-android,andyao/joda-time-android,lucasxas/joda-time-android,ptornhult/joda-time-android