ticket:10483: Update copyright & license dates, strip outdated info from readme, fix validation errs

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk@34880 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10591: Hoist setContext from SimpleDateFormat/RelativeDateFormat to DateFormat

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk@34881 251d0590-4201-4cf1-90de-194747b24ca1