Fixed #588 (partially, other places still need fixes)

Fixed #588 (partially, other places still need fixes)

EventRouter
 * is now thread safe
 * listenerList contains unique listeners, duplicates are not allowed

ListenerMethod
 * implemented proper equals and hashCode methods

AbstractComponent
 * @deprecated Use {@link #addListener(Class, Object, Method)} or
             {@link #addListener(com.itmill.toolkit.ui.Component.Listener)}
             instead. Using this method is discouraged because it cannot
              be checked during compilation.

svn changeset:3681/svn branch:trunk