Now we have the following concepts:

1) KisRestrictedSharedPtr --- a KisShared-based shared pointer that
   forbids implicit creation of a shared pointer from raw pointer.
   One should first create a usual shared pointer and assign it to
   a restricted one. Is resolves the issue of accidentally passing
   this pointer into a shared pointer and getting into troubles because
   of that.

2) KisPinnedSharedPtr --- a KisShared-based shared pointer that forbids
   implicit conversion into a raw pointer. Therefore, you cannot delete
   this pointer.

3) When we port the settings into QSharedPointer, both classes will not
   be needed anymore, because QSharedPointer has both the properties :)