Moved ancillary files to extras/ (fixes #1011)

extras/tests/catch/CMakeLists.txt

@@ -0,0 +1,18 @@
+# ArduinoJson - arduinojson.org
+# Copyright Benoit Blanchon 2014-2019
+# MIT License
+
+add_library(catch
+	catch.hpp
+	catch.cpp
+)
+
+target_include_directories(catch
+	PUBLIC
+	${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+	# prevent "xxx will change in GCC x.x" with arm-linux-gnueabihf-gcc
+	target_compile_options(catch PRIVATE -Wno-psabi)
+endif()