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>
diff --git a/configure.ac b/configure.ac
index ee59b03..3a528f2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -407,6 +407,7 @@
 	tests/modeprint/Makefile
 	tests/modetest/Makefile
 	tests/kmstest/Makefile
+	tests/proptest/Makefile
 	tests/radeon/Makefile
 	tests/vbltest/Makefile
 	tests/exynos/Makefile