activate graphs controller route for ontologies.
handle empty nodes and empty edges in graphs.
adjust graphs controller tests for empty results

- Test for return of valid response when calling
  graphs on logic/ontology without mappings/links
- Remove obsolete user portion (factory takes
  care of that).
Merge issue190... into augmenting112... for tabs

Merge 'origin/issue190-optimize_ontology_title_bar' into augmenting112_ontology_link_graph
Add Tests for determining Mapping-Class as Symbol.
implement passing version of mapping-query.
add graph as own view for graphs#index action.
Merge issue190... into augmenting112 for pages

Merge remote-tracking branch 'origin/issue190-optimize_ontology_title_bar' into augmenting112_ontology_link_graph
adjust js code to work with graphs#index view.
let graphs#index work as ontology#show subview.
let graph-js handle different mapping cases.
add handlebars as gem dependency.
refactor and add graph-info code as handlebar.
use handlebar-templates instead of jquery-code.
replace hard-string with variable.
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.