* TickCodeInfo is renamed to TickCodesManager and moved to separate files
* Added more callbacks to avoid use of wxWidgets
* Added function for color picker rendering
* For string formatting is used Slic3r::format instead of GUI::format (To avoid including wx/string)
* All code related to DoubleSlider extracted from Slic3r name space
+ "DoubleSlider: file is split to DoubleSliderForGcode and DoubleSliderForLayers in separate files
+ Suppress to add/delete ticks on update layers_slider from canvas when an application is a GCodeViewer
+ epsilon() is moved from DoubleSlider name space to CustomGCode