Fixes #2850
Update text + formatting
Merge pull request #2853 from sumobi/issue/2852

Update text + formatting
Merge pull request #2851 from sumobi/issue/2850

Fixes #2850
Set default quantity to 1 in ajax processing
Absint quantity in ajax processing
Use has_equals() for validating API request
Introduce hash_equals() function if it doesn't exist
Prevent non-object errors on in-browser receipt. CLoses #2854
Fix improper cap check
Version bump and changelog for 2.2.1