Grab focus when pushing the application

[ysbaddaden]

Follow up to #11 presenting the application isn't always enough. The window is unminimized, put above other applications, and so on, but the window doesn't necessarily grab the focus.

For example, while writing this issue, the Brium window behind Firefox will be put over the Firefox Window, but Firefox will keep the focus. I must Alt+Tab to switch to the Brium app.

[ysbaddaden]

I'm afraid this bug is dependent on the operating system window manager. ElementaryOS 6.1 seems to fail to give the presented window focus.