A few porting issues to change property names and handling of a few special items.
Add feed file compression.
Add permalink handling to allow munging the link for specific merchants behaviors.
Update google_merchant_availability method to 2.0
Property tweaks, they were invalid
Return validation as a tuple, so we can report the error
Merge remote-tracking branch 'origin/master'

Conflicts:
	lib/spree_google_merchant/feed_builder.rb