Table rework and color palettes

This release changes the way Tables are built for more flexibility and to fix some bugs. Some features were modified which introduces breaking changes from 0.3.0. See the CHANGELOG for details.

New features are also introduced, revolving around color support. The xcolor LaTeX package is now supported. Furthermore, we introduce ColorMap objects, which allows to define colors automatically. Plot objects are also fully integrated with the new Palette objects for easy and colorful plots.