APT source whitelist request for libvips-dev

[BanzaiMan]

This replaces travis-ci/travis-ci#4515.

The original text by @gasi follows

---

Supersedes: travis-ci/travis-ci#4398

This is needed to build the Node.js image library sharp which uses VIPS: https://github.com/lovell/sharp/

Script

before_install:
  - echo "Installing libvips..."
  - sudo add-apt-repository -y ppa:lovell/precise-backport-vips
  - sudo apt-get update
  - sudo apt-get install -y libvips-dev

See: lovell/sharp#187 (comment)

/cc @lovell

[raphaelokon]

Hi! We are using Travis Pro and would move to the container based infrastructure, but are unfortunately blocked by sharp. Is this merge happening anytime soon?

[gasi]

👍 We’d love to leverage Travis Pro’s new container based infrastructure as well 😄 Is there any way we can help move this along?

[raphaelokon]

+1