readme: remove logo as it looks awful

we need to re-size it somehow and get it to fit on the right-hand
corner.
sml: move flat name builder to cpp model

- remove the cpp prefix from the methods in builder
diagrams: minor cosmetic refactor of sml
sml: implement consumption workflow

- refactor old enricher code into the shape required for the new
  consumption approach
- made all methods in the consumer interface const for now
- add cycle detection to grapher