Compare by seconds instead of date value

Existing code will always calculate `$today` as less than `$days_to_week_start` except on Sundays and Mondays where `$days_to_week_start` is `0` and `1` respectively.

This ensures the comparison is made with the converted value so that a proper check is performed. This could also probably use a regression test.
#2585 - Initial pass at allowing price_id in the purchase links
Removing 'checked' from hidden input
#2585 - adding price_id to the edd_price shortcode
#2589 - Update edd_earnings_total when payment total price is changed
Check if price_id exists within prices
Merge pull request #2644 from elliott-stocks/patch-10

Check if price_id exists within prices
Update .travis-old.yml
Update install-wp-tests.sh
Update admin-footer.php
Update CONTRIBUTING.md
Update contextual-help.php
Update sample-products-import.xml
Fixes #2646
#2585 - Fixing undefined variable error and adding unit test for edd_price
#2585 - Making variable price JS logic more isolated
#2500 - Verify updating a payment was successful before editing post_meta
#2610 - Proposed UI update for price_id display
Merge pull request #2649 from cklosowski/issue/2500

Verify updating a payment was successful before editing payment_meta
Move edd_update_edited_purchase and wp_update_post higher up so that it runs before any ther payment data is changed. If we can't update the main payment record, nothing else should change. #2500