The test suite needs to compare greyscale images and was picking an
undefined byte in the pixel data on big-endian. Select a byte that works
on any endian instead.
See: #200
Meson files are normally using 4-spaces to indent and functions use first
parameter on the same line while others at next indentation level, not
following the parenthesis indentation.
So adapt libfprint to follow the meson standard.
The tests cannot work without the introspection bindings. So put them
into a corresponding if branch and also add the correct dependency on
libfprint_typelib for them to be run.
As the driver is not a normal image device, we need to add a custom
script to test it. Note that the ioctl dump must also be manually
modified unfortunately as the state is tracked incorrectly for the
device by umockdev-record.
