Coverage : bypass GridCoverageBuilder to create slice and add crs not null test.
widget : listen to layer style change in colormap editor.
Render2D : fix point symbolizer not applied on coverage layer
Render2D : fix text symbolizer not applied on coverage layer (by jsorel)
Go2 : dynamic palette when no colormap set on 1band images  (by jsorel)
Fix JUnit tests.
Coverage : revert bypass on PyramidalCoverageReader.