Auto merge of #1520 - glennw:slow-builds, r=kvark
Auto merge of #1520 - glennw:slow-builds, r=kvark

Temporarily disable nightly builds to allow some PRs to land.

<!-- Reviewable:start -->
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/webrender/1520)
<!-- Reviewable:end -->

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender