Editor: remove unused member TimeControl
MainWindow2: prepare to move TimeLine
TimeLine: split TimeLineCells to a new file
TimeLine: code cleanup
TimeLineCells: code cleanup
Editor: move timeline step 1
Editor: move timeline to MainWindow2
MainWindow2: remove duplicated connections
minor cleanup
Editor: remove unused method showPalette()
ToolOptionDockWidget: rename choseColour to colorChooseButton
Editor: move method importPalette(), exportPalette() to MainWindow2
MainWindow2: fix connection setOpacity(int)
Editor: merge changeColour() updateColour() to one new method setFrontColour()
ToolSet: remove the color value of each tools

--HG--
branch : colorsimp
Properties: remove member color. Now "color" is independent of tools.
only one global color exist.

--HG--
branch : colorsimp