Add libclang support for namespace aliases (visitation + USRs) along
with a new cursor kind for a reference to a namespace. 

There's still some oddities in the source location information for
NamespaceAliasDecl that I'll address with a separate commit, so the
source locations displayed in the load-namespaces.cpp test will
change.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@112676 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed