EXTAspect: support getters & setters at the same time

Don't always break out of the "find getter and setter" loop as soon as one
of them is found; if there are advices for both, loop needs to keep
looking for the other one.

And a unit test for it.
Merge pull request #39 from lpgagnon/master

EXTAspect: support getters & setters at the same time