Focus the schedule dialog box when it pops up

Gives the schedule dialog box a tabIndex of 0 so that
it can be focused, and then focuses it.
The call to focus is in render, since I couldn't figure out
how to place it in initialize, since not enough is loaded yet.
That might be a horrible mistake, please fix that.

Now the dialog box closes when esc is pressed, like normal.

Fixes #196
nit: For jQuery elements, our naming convention is to preface them with a `$`. Also, we use camelCase for variables in JavaScript. So `dialogbox` => `$dialogBox`

Also, could you add a comment above the line on the problem it's intended to fix?