Add material database for all attributes

[Michael Kahle]

There are many moduls and dialogs, where you can set specific attributes to parts like density, color, hatch pattern, transparency, reflectance, pressfit, specific thermal and stress values, rendering texture, ...

It would be much better to collect them all into one central material database and change them for a part by assigning a material to it.

Just think of the many steps you can save when investigating the different consequences for changing from one sort of plastic to another one.