Revert "Changed urls to url in forms, API, scrapers, coffeescripts, tests. Fixes #115"

This reverts commit 596ef0ea9c45248e5880f66e420484723ec4a84a.
Revert "Changed url to urls in fixtures"

This reverts commit 8477fe85415d8515d5fa80e5363d5706c5089621.
Revert "Added migration to change urls to url in Paper"

This reverts commit 01ec33ef49e8787e017cd006ee185406daf68ef5.
Revert "Changed urls to url in Paper model"

This reverts commit c11cd3bd93fbeb52d59d9496097dc7f961dd2323.