Include appropriate X11 libs to allow CrashPlanDesktop app to run

[Halfwalker]

It would be nice to be able to run the CrashPlanDesktop app via a docker exec -it crashplan /var/crashplan/app/bin/CrashPlanDesktop. That would save needing to have Crashplan installed locally anyway just to get the app. With appropriate forwarding of ~/.Xauthority, /tmp/X11-unix and DISPLAY env, it should work.
Looks like there are some missing gtk libs.

bash-4.3# cat /var/crashplan/app/log/ui_error.log 
Exception in thread "main" java.lang.UnsatisfiedLinkError: Could not load SWT library. Reasons: 
	Can't load library: /tmp/.cpswt/libswt-pi-gtk-4427.so
	Can't load library: /tmp/.cpswt/libswt-pi-gtk.so
	no swt-pi-gtk-4427 in java.library.path
	no swt-pi-gtk in java.library.path
	/tmp/.cpswt/libswt-pi-gtk-4427.so: libgtk-x11-2.0.so.0: cannot open shared object file: No such file or directory