* Add support for expiration_interval in Push

* Support expiration_interval for immediate pushes

* Test

* Add 'expiration_interval' to _PushStatus class

* Fix coverage

* capture and log exceptions caused by afterFind

* Wording

* Consolidated promise chaining

* use logger instead of console

* Adds support for read-only masterKey

* Adds tests to make sure all endpoints are properly protected

* Updates readme

* nits

* Add relative time queries

* Encode successful result

* Add integration test

* Add more error cases

* Remove unnecessary new Date

* Error when time has both 'in' and 'ago'

* naturalTimeToDate -> relativeTimeToDate

* Add $relativeTime operator

* Throw error if $relativeTime is invalid

* Add integration test for invalid relative time

* Exclude $exists query

* Only run integration tests on MongoDB

* Add it_only_db test helper
https://github.com/parse-community/parse-server/blame/bd2ea87c1d508efe337a1e8880443b1a52a8fb81/CONTRIBUTING.md#L23

* Handle where val might be null or undefined

* Add integration test for multiple results

* Lowercase text before processing

* Always past if not future

* Precompute seconds multiplication

* Add shorthand for interval
hr, hrs
min, mins
sec, secs

* Throw error if $relativeTime is used with $exists, $ne, and $eq

* Improve coverage for relativeTimeToDate

* Add test for erroring on floating point units

* Remove unnecessary dropDatabase function

* Unit test $ne, $exists, $eq

* Verify field type

* Fix unit test for $exists
Unnest query object