Fix for 1.3.x branch

See #3088
Merge branch 'Just-m-JM-fix-#3030' into 1.3.x
Merge branch 'Variations-API-fix-again' of https://github.com/crunnells/shopp into crunnells/pr/3090
Fixed versioning
Synced product.addons and product.variants loops
Merge branch 'crunnells/pr/3090'