    elementView.addTools(toolsView)

Add the provided `toolsView` (of the `joint.dia.ToolsView` type) to the element view.

Adding a tools view to an element view is the last (third) step in the process of setting up element tools on an element view:

    // 1) creating element tools
    var boundaryTool = new joint.elementTools.Boundary();
    var removeButton = new joint.elementTools.Remove();

    // 2) creating a tools view
    var toolsView = new joint.dia.ToolsView({
        name: 'basic-tools',
        tools: [boundaryTool, removeButton]
    });

    // 3) attaching to an element view
    var elementView = element.findView(paper);
    elementView.addTools(toolsView);

Every element view we want to attach to requires its own tools view object (`ToolsView` objects are automatically reassigned to the last element view they are added to). Similarly, every tools view we create requires its own set of tools (`ToolView` objects are automatically reassigned to the last `toolsView.tools` array they were made part of).

The element tools are added in the visible state. Use the `elementView.hideTools` function if this behavior is not desirable (e.g. if you want the element tools to appear in response to user interaction). Example:

    elementView.addTools(toolsView);
    elementView.hideTools();

    paper.on('element:mouseenter', function(elementView) {
        elementView.showTools();
    });

    paper.on('element:mouseleave', function(elementView) {
        elementView.hideTools();
    });