* simplified the traits::dimension for Eigen matrices
* added some tests for traits::identity and traits::zero
* got rid of a compiler warning (signed vs. unsigned) in Matrix.cpp
ChartValues are GenericValues and a Chart, which defaults to DefaultChart
had to make charts functional (ie no storage of the chart origin) so that they could be zero sized base class
otherwise there would have been a double of the memory for values (ones for the value, and once for the chart origin, which default to the same)
most tests work, execept for serialization based stuff, and const filtering of values.