remove obsolete jit-based graph code.
add hamlbars gem for 'hb'-helper support.
include module to fetch aggregated data

We need some aggregated data for the graph
representation (symbols count for example),
the new aggregate method fetches this data.
adjust js-code for aggregates

- Add Symbol-Count to Ontology-Node
- Add "all" attributes to Link-Edge
- Push aggegrate data from controller
  to json.
adjust graphs-controller test for html template.