Revert "Amazon, use concurrency safe enhance_referent"

This reverts commit 17d6d58342f9ab7867bb08aa7c5aa157e74358a1.
make Referent.add_identifier threadsafe with_connection
list_with_limit use .list-unstyled for bootstrap3
proxy_like_headers, for now fix Accept-Encoding to always ask for identity, no gzip'd
association :includes make work for Rails3 OR 4.1
ServiceResponse, make initializer agnostic as to arrity, to work in multiple rails versions
cover_image, force default box-sizing so image size stays how it was in bootstrap2