RestAPI for model2SVG

[h3ssto]

• In: Feature Model in FeatureIDE XML
• Out: SVG (via the FM Viewer/Editor renderer)

Extensions:

• Support for collapsing (max-height, max-width, max-children)
• Support for coloring (via additional supplied JSON)
• Support for listing cross-tree constraints below the the FM
• Support for adding a legend for all used elements

Finally:

• Migrate Viewer/Editor implementation to use the same API