[Flash] Make stage properly capture clicks

[odnamrataizem]

This makes the stage capture click events instead of mouse downs. As such, it can be checked whether the user actually clicked the stage rather than a button on the controls bar (or the controls bar itself) before sending the event to the DOM.

This should fix a bunch of related issues, like #742.

[odnamrataizem]

Yep, just that.

[odnamrataizem]

Oh CRAP nvm, I forgot there was another change there, sorry. This one is essential to properly fix #742 so it only sends back to the DOM clicks to the stage.

FlashMediaElement.stageClicked() should look like this:

function stageClicked(e:MouseEvent):void {
    //_output.appendText("click: " + e.stageX.toString() +","+e.stageY.toString() + "\n");

    // only send event if user actually clicked the stage
    if (e.target == stage) {
        sendEvent("click", "");
    }
}