Adding data formatters for iterators for std::map and std::vector (both libc++ and libstdcpp)
This does not include reverse iterators since they are both trickier (due to requirements the standard imposes on them) and much less useful
llvm-svn: 175787
Split some NS* formatters in their own source files
Refactored a utility function for the C++ formatters to use
Fixed the skip-summary test case to be explicit about requiring libstdc++ for operation
llvm-svn: 175323
