css overflow on the popper = bad placement

[ocombe]

CodePen demo

http://codepen.io/anon/pen/egZyZQ

Steps to reproduce the problem

1. add the css property overflow: auto (or any other overflow value) on your popper div
2. set the placement option to any value (ex: "left")
3. the popper is always at the bottom left, whatever the value of placement. It gets even worse on "fixed" poppers because it will stay at the top of the window

What is the expected behavior?

Using placement should place the popper, even if it has an overflow set

What went wrong?

The popper isn't positionned because of the "overflow" css property :'(

Any other comments?

By the way, the link to the popper.js lib in your codepen example (given in the issue template) doesn't work: http://rawgit.com/FezVrasta/popper.js/master/src/popper.js --> 404
I used unpkg.com instead: https://unpkg.com/popper.js@1.0.2