add hard-coded Last-Modified headers on GET requests so CDNs will be tricked into caching them.  Also, respond to any GET request with If-Modified-Since with 304, since manifests and blocks are always immutable.
add hard-coded Last-Modified headers on GET requests so CDNs will be
tricked into caching them.  Also, respond to any GET request with
If-Modified-Since with 304, since manifests and blocks are always
immutable.

syndicate-storage/syndicate-core,syndicate-storage/syndicate-core,iychoi/syndicate-core,iychoi/syndicate-core,syndicate-storage/syndicate-core,iychoi/syndicate-core,syndicate-storage/syndicate-core,iychoi/syndicate-core