client: Indicator fills height

Otherwise we can't interact with children.
client: AppChooser visibility depends on button checked flag

Clicking on the button toggle the checked flag which in turns drives
AppChooser visibility.
server: only send the relase button event on the wl_hawaii_desktop_shell_grab interface

Signed-off-by: Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>
Edited-by: Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>
client: emit PopupWindow::visibleChanged() only when appropriate

Connect the underlying window's visibleChanged(bool) signal to our
visibleChanged() signal so that it is emitted when the window visibility
is really changed.

Issue: #96
client: AppChooserButton checked property mapped to visibility

AppChooserButton checked property depends on AppChooser visible
property.

Issue: #96