qdoc doesn't sort class listings properly

Attached module seems to produce unexpected order for classes

To reproduce:

• make sure the paths in qdocconf point to correct places
• run: qdoc testmodule.qdocconf -I inc -I inc/testmodule
• open doc/index.html

Classes are ordered: Third, First, Second

Swapping the file name of the header files around seems to affect the order they appear in, so it looks like might prefer the file name rather than the class name for ordering, but that doesn't always work like that either.