* modified plugin access from Ribbon so it use only plugin class name
(no more reference on PluginDescriptor).
* added Plugin.getResource(..) and Plugin.getResources(..) methods.
* added predefined alpha colormap.
* main interface do not anymore combine events for ROI/Painter
add/remove operation (more practical for developer but can make
application slower).
* PluginClassLoader:
 - removed Osgi loader (not needed there).
 - some fixes.
 - improved performance.
* fixed sequence direct save operation which was locking interface.
* better default colormaps for image containing more than 3 channels.
* reintroduced old ROI constructors (for backward compatibility).
* no more ROI/Painter remove event from a closed sequence.
* fixed minors bugs.
updated header
* new SequenceBuilder class to help in building a sequence
with multi-threaded algorithms.
* IcyBufferedImage:
 - added method to load only a sub part of an image.
 - minor speed improvement in loading some multi channel image.
 - better default channel colors.
* improved error handling with NetworkUtil.download(..) method.
* modified classpath & manifest to reflect libraries changes.
* refactoring.
updated.