Bug 318944 CSSSWTEngineImpl leaks memory
CSSSWTEngineImpl stores too many element contexts. In a memory snapshot, the HashMap size was 15559. This is most probably a leak.
bundles/org.eclipse.e4.ui.css.core/src/org/eclipse/e4/ui/css/core/impl/engine/AbstractCSSEngine.java
* Set the CSS Error Handler to manage exception.
	 */
	public void setErrorHandler(CSSErrorHandler errorHandler) {
		this.errorHandler = errorHandler;
	}
	
	public IResourcesLocatorManager getResourcesLocatorManager() {
		if (resourcesLocatorManager == null)
			return defaultResourcesLocatorManager;
		return resourcesLocatorManager;
	}
	public void setResourcesLocatorManager(
			IResourcesLocatorManager resourcesLocatorManager) {
		this.resourcesLocatorManager = resourcesLocatorManager;
	}
	
	public DocumentCSS getDocumentCSS() {
		return documentCSS;
	}
	public ViewCSS getViewCSS() {
		return viewCSS;
	}
	public void dispose() {
		reset();
		
		Collection contexts = elementsContext.values();
		for (Iterator iterator = contexts.iterator(); iterator.hasNext();) {
			CSSElementContext context = (CSSElementContext) iterator.next();
			Element element = context.getElement();
			if (element instanceof CSSStylableElement) {