Update some dependencies, fix some deprecation warnings

[DeeDeeG]

Context & Summary of Changes

• Fix a couple of deprecation warnings (see #602)
• Update some dependencies

Checklist

• [ ] Tested Mobile Responsiveness
• [ ] Added Unit Tests
• [x] CI Passes
• [ ] Deploys to Heroku on test Correctly (Maintainers will handle)
• [ ] Added Documentation (Service and Code when required)

[DeeDeeG]

CI on this won't pass, due to the issue solved in #608. I tried with that commit merged to this locally, and CI passed.

Edit: #608 is merged into develop, so the "merge commit" of this into develop, which Travis CI tests, now passes.