ticket:10258: Parse different variations of '+' and '-' when isLenient is set in C++.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/tkeep@33988 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10274: Remove branch.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/tkeep@33990 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10258: Remove branch.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/tkeep@33991 251d0590-4201-4cf1-90de-194747b24ca1