sky modal opens on left side of page IE 11

[Blackbaud-BrandonHay]

Expected behavior

when opening a modal we expect it to open in the center of the page

Actual behavior

On IE 11 modal opens on left side of the page, despite its margin: 0 auto property being set

Steps to reproduce

was unable to get your modal component working in a plunker but you can view this on your skyux2 components demo page: https://developer.blackbaud.com/skyux2/components/modal. just open the modal

[Blackbaud-PatrickOFriel]

In 2.0.0-beta.4