add functionnality to attach image files in chat

.../java/fr/ill/ics/client/control/chat/ChatFileManager.java

src/main/java/fr/ill/ics/client/test/ImageFromByteArray.java

src/main/java/fr/ill/ics/client/view/chat/swt/SWTChat.java

...r/ill/ics/client/view/command/swt/SWTCommandZonePeer.java

...a/fr/ill/ics/client/view/factory/CommandImageFactory.java

...ain/java/fr/ill/ics/client/view/factory/ImageFactory.java

.../fr/ill/ics/client/view/util/imageviewer/ImageViewer.java

.../ics/client/view/util/imageviewer/swt/SWTImageViewer.java

...va/fr/ill/ics/client/view/util/textviewer/FileViewer.java

...ll/ics/client/view/util/textviewer/swt/SWTFileViewer.java