TODO

- Reimplement in LibertyEiffel

- Turn Nodes and Beams objects into proxy to the data contained in the global matrices of Truss (Flyweight patter http://en.wikipedia.org/wiki/Flyweight_pattern ); i.e. Truss contains all the matrices/array usually required to solve a static linear system while Nodes and Beams will hold only topological data (which beams are connected to Node n?), a reference to its truss and an index.

- Currently View and Model are melt together. This is not good at all. Separate them into Model (Node, Beam and Truss) and View (NodeRenderer, BeamRenderer and TrussRenderer).

- In fact view uses monitor coordinates with y growing downwards while the model needs the second coordinate growing upward, since the cross product x^y shall point outside the screen, representing counterclockwise rotations as positive.

GUI:
- +/- keys to zoom in and out
- click on beam to zoom on that beam
- add animation to zoom to beam
- drag to pan
- double click to change nodes and beams
- gestures

--- remove output to stdout and stderr