Create demo application

CMakeLists.txt

@@ -3,6 +3,7 @@ cmake_minimum_required(VERSION 3.15)
 project(imp LANGUAGES C)
 
 option(TESTS "Build tests" ON)
+option(DEMO "Build demo" ON)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
@@ -23,3 +24,7 @@ if (${TESTS})
   add_subdirectory(dep/unity)
   add_subdirectory(tests)
 endif()
+
+if (${DEMO})
+  add_subdirectory(demo)
+endif()