Bug Bug 482225 - decltype(auto) not parsed

* Adapted the parser to cope with decltype(auto)
* Extended IASTSimpleDeclSpecifier to have a kind for decltype(auto)
* Added tests (syntactic recognition and type deduction for variables)
* Modified DeclSpecWriter to cope with the decltype(auto) kind simple
decl specifier

Change-Id: Ib1ded823027d124cef35e9d6355c0f48f57709a0
Signed-off-by: Thomas Corbat <tcorbat@hsr.ch>
7 files changed