Fixes #1404 URL encode dates for query params

Created by: james-rantmedia

This change URL encodes a date string before it is added as a query parameter to prevent a possible + character being mistaken for an encoded space as opposed to the timezone adjustment.

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Description of the PR

This PR addresses issue #1424 (closed) by URL encoded date strings before adding them as URL query parameters, to prevent the + in the timezone adjustment from being mistaken as an encoded space.

cc @jgavris (2017/07) @ehyche (2017/08) @Edubits (2017/09) @jaz-ah (2017/09) @d-date (2018/03) for review