qt5natvis

All .natvis files for Qt5 that I have ever found didn't represent certain types properly in CLion (and probably in other IDEs too).

Fixes:

• The AlternativeType tag doesn't seem to work well. All entries that had aliases declared this way were extracted into standalone entries. This affects types like QStringList.
• Convenient fast lookup added to smart pointers as Value. It won't be shown for null pointers.