The widget prints a number of arrows one by one to indicate a sliding
direction. Number of arrows and animation duration are configurable.

On button press send out the number changed signal at the very end so
listeners can process the button event prior to the number update event.

This also makes sure we don't send multiple number changed events
when nothing changed.

Add a new boolean "show-action-buttons" property that specifies
whether the submit and delete buttons are displayed.

This allows to access the documentation from within glade.

This avoid hardcoding values when we can put them in the UI description.

This avoid overridding with the one we set in the the .ui file of the
window.

Use gchar instead of char, use GNOME style pointer spacing and name the
number parameter 'number'. This is all cosmetic but will make the code
look a bit more GNOME-like.

Sanitize the parameters of the 'number' property accessor. This will
warn or misusages of the API at runtime and avoid potential crashes.

This is necessary for introspection to know the header file to use.

This makes factorizes the homogeneity functions of HdyLeaflet to make
the code a bit shorter.

See dpkg-buildpackage(1). This allows us to skip the tests e.g. on
aarc64 with armhf emulation since running xvfb fails there.

Emit symbol when delete button was clicked.

This signal is emitted when a symbol button (numbers or '#' or '*')
is clicked.

This will make future adjustments like attaching s.th. to all buttons.

We don't perform a copy.

Use proper names and mention HANDY_USE_UNSTABLE_API.

The object's _init() function is only meant for basic setup so that
properties can be processed, all the rest should be done in
_constructed.