[Meta] Introduced AURORA_PP_LIMIT constant
[SmartPtr] Factories: Automated code generation even more
[All] Various minor improvements
[SmartPtr] Explained back-end implementation
[SmartPtr] Optimized makeCopied()

Also split Factories.hpp into MakeCopied.hpp and MakeUnique.hpp, and provided versions based on variadic templates. The split allows more selective inclusion and doesn't require to carry along the whole <memory> header if only aurora::CopiedPtr is used.
[SmartPtr] Removed copied()
[SmartPtr] Fixed bug with derived-to-base conversion
[SmartPtr] Added classical move ctor/op= to provide nothrow guarantee
[SmartPtr] Fixed problem with cloner exception safety
[SmartPtr] Avoided unnecessary allocation for nullptr