First experiments with the palette - code mainly from openJUMP
Some methods from the TocRenderer may be useful in other places.
Improves the cntent of the JComboBox : we now have a preview of the
palettes :-)
Move setFieldState in a Utility class
Rework the ColorConfiguration panel
IMproves the integration of palettes.
They are now usable as well as gradient are !
Fix the layout of the ColorConfigurationPanel.
Fix quantiles implementation
Replace a text field by a combobox.
Thanks to that, we will be able to propose only the supported number of
thresholds in the generated classifications.
See #451
Adds javadoc in some places and a test for ColorScheme.getSubset
improves javadoc
fixes the loading of color schemes
Merge pull request #455 from agueganno/palette-tests

Palette integration in the Simple Style Editor

Integrates palettes in the Simple Style Editor. The code was originally taken from openJUMP and then simplified and documented. We have a class representing palette that is used later on in the interface.