cpp11-migrate: Add Replace-AutoPtr Transform

Add a new transform to replace uses of 'std::auto_ptr' by 'std::unique_ptr'.
Copy-ctor and assign-operator are wrapped with a call to 'std::move()'.

Note that until header modification is ready it is not that useful, that's why
it's marked as (EXPERIMENTAL) in the command line description and a "Known
Limitations" section is present in the transform documentation.

Author: Guillaume Papin <guillaume.papin@epitech.eu>
llvm-svn: 185535