ticket:10802: Document that createObject must add a reference to what it returns. Change all client code of cache to do this. Add a U_ASSERT in UnifiedCache to ensure that createObject returns an object with a hard reference.

git-svn-id: http://source.icu-project.org/repos/icu/icu@36173 251d0590-4201-4cf1-90de-194747b24ca1
ticket:9063: improve docs around ucnv_getMinCharSize and ucnv_getMaxCharSize to reflect that they are in code points and UChar code units, respectively.


git-svn-id: http://source.icu-project.org/repos/icu/icu@36174 251d0590-4201-4cf1-90de-194747b24ca1