add arduino json lib

#182

lib/ArduinoJson/test/IntegrationTests/CMakeLists.txt

@@ -0,0 +1,18 @@
+# ArduinoJson - arduinojson.org
+# Copyright Benoit Blanchon 2014-2018
+# MIT License
+
+add_executable(IntegrationTests 
+	gbathree.cpp
+	round_trip.cpp
+)
+
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+	target_compile_options(IntegrationTests
+		PUBLIC
+		-fsingle-precision-constant # issue 544
+	)
+endif()
+
+target_link_libraries(IntegrationTests catch)
+add_test(IntegrationTests IntegrationTests)