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.
#2610 - Proposed UI update for price_id display
Check for SKU before ID when setting up the [purchase_link] short code. We have to check for SKU first because the ID defaults to the current post ID, so it is always present. Closes #2666
Merge pull request #2670 from cklosowski/issue/2610

UI Update to show the price_id in the Download Pricing Metabox
Spelling tweak

Fixed localization bug
Remove accidential cart fees attached to cart items. Closes #2672
Merge branch 'master' of github.com:easydigitaldownloads/Easy-Digital-Downloads
Improve consistency of widget Initialization.

When trying to work directly with registered widgets, Categories/Tags
Widget and the Download Cart Widget behave oddly. Specifically,
calling the  method would not save the widget.

It turns out that these widgets are initialized in strange ways:

* Constructors for the widget are the name of the class, which is only
  necessary in PHP4. Using  is sufficeint as EDD does not
  support PHP4 and it brings these widgets in line with current best
  practices and the Product Detail Widget.

* The first argument in the parent class constructor was passed as
  . This argument sets the base ID for the widget.  means
  nothing in this case. This was updated to an appropriate value.

Fixing these two issues fixes my use case, as well as brings the widget
in line with best practices.
Fix undefined index notices when no downloads exist.
Fix undefined indices in Download Cart widget.
Fix undefined index notices in Categories/Tags Widget.
Merge pull request #2673 from tollmanz/consistent-constructors

Improve consistency of widget Initialization.
Merge pull request #2674 from tollmanz/undefined-index-notices

Undefined index notices in widgets
Load text domain on plugins loaded. #2677
Merge branch 'master' of github.com:easydigitaldownloads/Easy-Digital-Downloads
Add correct microdata
Merge pull request #2679 from sumobi/issues/2678

Add correct microdata
Use ! empty instead of isset when checking for the SKU #2666
Cleanup edd_add_discount()
Cleanup edd_edit_discount()