Remove CATCH_CONFIG_DISABLE_MATCHERS

Now that the recommended distribution and usage method is proper
library, users can just avoid including the matcher headers to get
basically the same effect.

src/catch2/catch_objc.hpp

@@ -103,7 +103,6 @@ namespace Catch {
         return noTestMethods;
     }
 
-#if !defined(CATCH_CONFIG_DISABLE_MATCHERS)
 
     namespace Matchers {
         namespace Impl {
@@ -193,8 +192,6 @@ namespace Catch {
 
     using namespace Matchers;
 
-#endif // CATCH_CONFIG_DISABLE_MATCHERS
-
 } // namespace Catch
 
 ///////////////////////////////////////////////////////////////////////////////