Added symbolic evaluation of quantity.Symbolic. (This is necessary for some strange functions, see e.g. the corresponding unittest)
Simplified the "isempty" check for quantities

Added converter of quantity.Discrete to quantity.Function: a linear interpolation is used as valueContin$

Added help information for the plotEigenvalues function
Modified definition of signals.Piecewise

Important performance update transz_fast_nDim: matlab's matrix multiplication becomes very slow for large vectors. However, elementwise multiplication is ultra fast!
Example: a = ones(20000,20); b = ones(20,20000);
Now c = a*b is very very slow compared to
d = sum(a.'.*b,1)!

- checks numel
- better readable

- now also checks sizes
-

Removed exportData as property and added a converter for this class
Fixed integration for empty objects.
Fixed name of integrated quantities.

added functions misc.fold and misc.unfold to convert vectors/arrays from and to folding representation