function setLauncher(launcher) {
        if (!(launcher && launcher.launch)) {
            console.log("Invalid launcher object: ", launcher, new Error("LiveDevMultiBrowser.setLauncher()"));
            return;
        }
        _launcher = launcher;
    }
Sets the current browser launcher mechanism to be used by live development
(e.g., default browser, iframe-based browser, etc.)
The launcher must provide the following method:

- launch(url): Launch the given URL in the appropriate browser.

@param {{launch: function(string)}} launcher