Add templates to Palette

[valeriosantarelli]

Add, through the Palette, through a new palette, or through some other kind of mechanism, the possibility to automatically add to the diagram a template for a complex ontology pattern. For instance:

• a hierarchy with 1 father concept and n child concepts (disjoint or/simple of)

• two concepts linked by a role

• a concept with one or more attributes

• etc. etc.