Update english dev agreement

From https://github.com/clouserw/zamboni/blob/a0ce6c2bef336b03d0e0d7fd42e062c860d41807/mkt/site/templates/site/dev-agreement.html
Exclude disabled apps from dumps (bug 889938)
fix docs whitespace
fix <address> tags for TOS (pl, es)
bumpsies
Added newlines to purchase receipt email (bug 889634)
this is terrible, but make app_to_dict fall back to the waffle flag (bug 889945)
update and localise our developer agreements: en-US, es, pl (bug 872799, bug 887373, bug 887384)
put operator shelf categories at the top of the API list (bug 889941)
order categories by weight too (bug 889941)
Add bango agreement (bug 889855)
update dev agreements to point to @mattbasta's beautiful page o' bango wonder (bug 872799)
Unindex apps/addons after the save() (bug 890080)
allow through prepareJWT (bug 890078)
Use django storage for dump_apps.
Fix for urllib2 not throwing errors on bad connection (bug 878368)
Update prod.txt

Bump boto and django-storages.
Use json_view.error for JSON views' errors
Fix references to site/dev-agreement.html
Merge pull request #878 from muffinresearch/890235

Fix references to site/dev-agreement.html