refactor(mixins): merge FollowUpProperty and MergeUpProperty mixins

The two mixins are now class methods provided by the AncestorsProperties
mixin that can be included in a class using Function::extend.
The Example class now use the new mixin.
refactor($core): extract nextTick as a spectacular method
chore($git): merge back changes from master in develop
feat(runner): add random execution as default behavior

The behavior can be enabled/disabled with --random and
--no-random options.
It's not 'fully' random yet, as there're dependencies
to handle and that tests are randomized per context.
feat($cli): add --colors options that forces the coloring

If the colors was disabled previously with --no-colors it
can now be enabled again with --colors.
The option was also renamed in the option object in order
to be more consistent with the other options.
fix(examples): examples groups without examples are now pending

It was supposed to be the case, instead it was leading to some
weird behavior such as timeout.
feat($browser): automatically hide success on the first failure