Text, IFont, IDrawable: Rename type definitions

* Text: Introduce type definition 'self_type'.
* Text: Rename type definition 'RawPtr' to 'raw_ptr'.
* Text: Rename type definition 'UniquePtr' to 'unique_ptr'.
* Text: Rename type definition 'SharedPtr' to 'shared_ptr'.

* IFont: Introduce type definitions 'self_type', 'unique_ptr'.
* IFont: Rename type definition 'RawPtr' to 'raw_ptr'.
* IFont: Rename type definition 'SharedPtr' to 'shared_ptr'.

* IDrawable: Rename type definition 'SelfType' to 'self_type'