Fix the time display of all day (and non-all-day) events, and handle all_day property

[osteele]

Description

09dbd6f Replace allDay -> all_day in server API

Starts #214

This allows the client to work with old- and new-API servers. Once the client is deployed through to production, and then the API server is deployed through to production and on dev branches, then the API version detection can be backed out.

0e2a206 Fixes #212 all-day events have end time, other events don't

Verified by manual inspection of the snapshot file. Now that this is done, the test should prevent regressions.

Required

Changes must conform to these requirements:

• yarn test passes. All new and existing tests pass.
• yarn lint passes. All new code follows the code style of this project.

Aspirational

We don't yet require these, but they are nice to have:

• New code is covered by new or existing tests.
• Changed code is covered by new or existing tests.

[osteele]

CI is failing because the tests assume they're running in EDT. This is fixed.

Adding the following to .travis.yml would fix it for Travis, but a developer running in a different TZ could still not run the tests. Also they would stop working when EST starts.

before_install:
- export TZ=America/New_York

[osteele]

CI is fixed for this PR.