Update importer for MU

closes #3285

- remove apps stuff for now
- if there is a single user, behave the same as before, overriding
  non-critical properties of the single owner user
- if there are multiple users, import them like normal resource
Remove unnecessary hard refresh on signout.

Refs #3488
- Hard refresh handled by ember-simple-auth.
Merge pull request #3494 from ErisDS/issue-3285

Update importer for MU
Update spam prevention

closes #3468
- added rate limit to deny more than 5 attempt every hour
- updated spam prevention to be configurable
- added config values spamTimeout, ratePeriod, rateAttempts
- added ratePeriod:1 to config.example.js to prevent functional tests
from hitting the rate limit
- commented spam test, I’ll fix it tomorrow
Merge pull request #3496 from jaswilli/refresh

Remove unnecessary hard refresh on signout.
Merge pull request #3486 from sebgie/issue#3468

Update spam prevention
Version bump to 0.5.0-rc1
Re-upgrading Casper
Fix tests to ensure correct post is being checked

Refs #3473
- Change tests to not assume that all inserted fixture data
  will end up with the same millisecond-precision time for
  results sorting.  If a test is set up to check the contents
  of a specific fixture extract it explictly from the results.
Merge pull request #3519 from jaswilli/tests-undefined-key

Fix tests to ensure correct post is being checked
Change user menu link to a button

Closes #3546

- Change user menu popover toggle from a <a> to a <button>
- Change tests accordingly