* TriEdgeCollapse is no more multiply derived but it get its "work on two vertex" behavior from a template parameter called VertexPair.
* EdgeCollapse is no more a class devoted to the simplification but it has been renamed as EdgeCollapser and it is a static class templates over a generic <VertexPair> that offer methods to perform Edge Collapses.
* cleaned up the parameter passing method for local optimization classes (and added a baseParameterClass from which every local optimization method must subclass its own parameters)