Convert some visible namespace from google_base to gm_.
Change upload filename to google_merchant.xml.
Remove cache keys from image links.
Feed formatting.
Add property storage for gender, age_group, color and size
Change product type to remove top level taxon.
Add support for adwords_grouping and adwords_labels attributes.
Prefix all image URLs with http://
Merge pull request #2 from rterbush/namespace-change

Convert some visible namespace from google_base to gm_