Improve tutorial example
This tutorial example only handles XCB_EXPOSURE and XCB_KEY_RELEASE events and ignores everything else. Thus, there is no point in asking for more kinds of events.
A while ago, I ported this tutorial to x11rb 1. Recently, I received a pull request 2 removing these unnecessary event masks. This commit is thus only partially by me and the 'issue' was originally found by the author of 2.
Signed-off-by: Uli Schlachter psychon@znc.in