* LUT is now saved in sequence persistent data.
* added multi selection support in Plugin browsers.
* fixed default image colormap.
* packed LociImporter class in LociImporterPlugin.
* rewrites and cleanup in the Plugin class loader (hopefully will fix
some random load class error).
* Modified XMLPreferences so it should be thread safe now.
* clean metadata on image loading.
* avoid useless Z and T numbering when saving as "multiple files".
* added missing plugins checking on start.
* some cleanup on PopupPanel component.
* minor changes/fixes on inspector layout.
* started some work on custom colormap representation in the combobox.