Don't introduce Catch::Matchers namespace in macro

- this could be a breaking change - fixed up self-test code to compensate

projects/SelfTest/TestMain.cpp

@@ -44,6 +44,8 @@ inline Catch::TestCase fakeTestCase( const char* name, const char* desc = "" ){
 
 TEST_CASE( "Process can be configured on command line", "[config][command-line]" ) {
 
+    using namespace Catch::Matchers;
+
     Catch::ConfigData config;
 
     SECTION( "default - no arguments", "" ) {