Update Arcanist config to point to reviews.llvm.org

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@210558 91177308-0d34-0410-b5e6-96231b3b80d8
A bunch of the char.traits tests were using unicode literals. #ifdef those bits out on c++03, since it doesn't support u"" and U "" style strings.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@210560 91177308-0d34-0410-b5e6-96231b3b80d8
Make the helper routines in string really be constexpr. This required a bit of refacoring in algorithm as well. Give them better names while we're at it. All of these are internal rotines; no visible functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@210561 91177308-0d34-0410-b5e6-96231b3b80d8