Left-shifted tooltips on SVG elements

Created by: BertrandBordage

See http://jsfiddle.net/hqDF7/ for a minimal example.

The issue appeared with 8534e125. Those lines use .outerWidth & .outerHeight and override what .getBoundingClientRect was returning. Unfortunately, .outer[Width|Height] always return 0 for SVG elements, while .getBoundingClientRect returns the expected output.

Removing the incriminated lines "fixes" the issue. But of course I guess it creates other issues.

This issue is similar to #5956 (closed).