can we extend this paragraph a bit? explain that the cmf block bundle *automatically* changes some defaults and adds configuration to the sonata block bundle to make it work nicely. then explain why we need the different template (compatible with both sonata and cmf blocks) and that people need to extend from this rather than the sonata one. or better yet use the config option.

the problem i see with listing the configuration in all formats here is that people could get the idea they have to copy this config into their project, which is totally not the case. maybe we should take it apart and explain it bit by bit. like "set template for block_base to...., register the RssBlock with a couple of settings...".