Relocate catch2 helper macros from alib2std

It really makes no sense to have it inside alib2std component. Moved
into separate tests/ folder.

CMakeLists.txt

@@ -34,6 +34,7 @@ include(CTest)
 if(BUILD_TESTING)
 	include(Catch)
 	add_subdirectory(lib/catch2)
+	include_directories(${PROJECT_SOURCE_DIR}/tests)
 	configure_file(
 		${PROJECT_SOURCE_DIR}/CMake/configure_tests.hpp.in
 		${PROJECT_BINARY_DIR}/configure_tests.hpp

alib2data/test-src/regexp/RegExpTest.cpp

-#include <catch2/extensions/HelperMacros.h>
+#include <testing.h>
 #include "sax/SaxParseInterface.h"
 #include "sax/SaxComposeInterface.h"

alib2std/test-src/extensions/FunctionalTest.cpp

-#include <catch2/extensions/HelperMacros.h>
+#include <testing.h>
 #include <alib/functional>

alib2std/test-src/extensions/TypeInfoTest.cpp

-#include <catch2/extensions/HelperMacros.h>
+#include <testing.h>
 #include <alib/string>
 #include <alib/iostream>

alib2std/test-src/extensions/container/VariantTest.cpp

 #include <catch2/catch.hpp>
-#include <catch2/extensions/HelperMacros.h>
+#include <testing.h>
 #include <alib/variant>
 #include <alib/set>
 #include <alib/algorithm>

alib2std/src/catch2/extensions/HelperMacros.h → tests/testing.h

-#ifndef _ALIB2STD_CATCH2_
-#define _ALIB2STD_CATCH2_
+#ifndef _ALT_CATCH2_HELPERS_
+#define _ALT_CATCH2_HELPERS_
 #include <catch2/catch.hpp>
@@ -8,4 +8,4 @@
 #define REQUIRE_IMPLY(x,y) REQUIRE ( ( ! ( x ) || ( y ) ) )
 #define REQUIRE_EXCLUSIVE_OR(x,y) REQUIRE ( ( ( !( x ) && ( y ) ) || ( ( x ) && !( y ) ) ) )
-#endif /* _ALIB2STD_CATCH2_ */
+#endif /* _ALT_CATCH2_HELPERS_ */