Use unique_ptr for d-pointers (#1095)

* clang-tidy: make deleted members public

One oversight of modernize-use-equals-delete is that the C++11 way of
doing this is to make it public, which makes the warning still trigger.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

* clang-tidy: add missing deleted functions

Found with cppcoreguidelines-special-member-functions

Signed-off-by: Rosen Penev <rosenp@gmail.com>

* unique_ptr conversions

unique_ptr is a safer and cleaner way to handle d pointers.

Also added missing = default.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

---------

Signed-off-by: Rosen Penev <rosenp@gmail.com>

tests/utils.h

@@ -139,6 +139,9 @@ public:
       deleteFile(m_filename);
   }
 
+  ScopedFileCopy(const ScopedFileCopy &) = delete;
+  ScopedFileCopy &operator=(const ScopedFileCopy &) = delete;
+
   string fileName() const
   {
     return m_filename;