tests: add proptest

A small program that allows us to see and modify properties.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rob Clark <robclark@freedesktop.org>
modetest: alpha buffers

Make upper-left corner for RGB32 buffers translucent, for testing
blending of AR24 vs XR24.

Signed-off-by: Rob Clark <robclark@freedesktop.org>
modetest: Print newline for empty blobs

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rob Clark <robclark@freedesktop.org>
update signed/object prop types

Signed-off-by: Rob Clark <robclark@freedesktop.org>