Simplify RedCachePipeItem code
RedCacheItem was using an union to reuse cache item memory as a pipe item to release that specific cache item. Instead of spreading that structure everywhere move the specific optimization all in cache-item.tmpl.cpp. This make also code less cluttered. Add some comment on specific code.
Move declaration on common graphics channel.
Simplify marshalling the message.
Edited by Frediano Ziglio