Mixin inheritance is an alternative to the usual
multiple-inheritance and solves the problem of knowing which
parent will be called. It also solves a number of tricky
problems like diamond inheritence.
The idea is to solve the same sets of problems which MI solves
without the problems of MI.
PR: 54746
Submitted by: Mathieu Arnold <m@absolight.net>
Approved by: fjoe (mentor)