Bug 150593 Enhancements for ResourceManager
The attached patch addresses the following in ResourceManager - Fixes several JavaDoc bugs - Adds a "getImage" method that implements the common pattern of "return existing image if known, or allocate a new image otherwise"
bundles/org.eclipse.jface/src/org/eclipse/jface/resource/ResourceManager.java
*
     * @param descriptor description of the font to destroy
     */
    public final void destroyFont(FontDescriptor descriptor) {
        destroy(descriptor);
    }
    
    /**
     * Disposes any remaining resources allocated by this manager. 
     */
    public void dispose() {
        if (disposeExecs == null) {
            return;
        }
        
        
         
        
        
        RuntimeException foundException = null;
        
        Runnable[] execs = (Runnable[]) disposeExecs.toArray(new Runnable[disposeExecs.size()]);
        for (int i = 0; i < execs.length; i++) {
            Runnable exec = execs[i];            
            
            try {
                exec.run();
            } catch (RuntimeException e) {