Big assertion capture refactoring.

- moved as much logic out of the macros as possible
- moved most logic into new ResultBuilder class, which wraps ExpressionResultBuilder (may take it over next), subsumes ResultAction and also takes place of ExpressionDecomposer.

This introduces many SRP violations - but all in the name of minimising macro logic!

include/internal/catch_debugger.h

@@ -43,7 +43,7 @@ namespace Catch{
 #endif
 
 #ifndef CATCH_BREAK_INTO_DEBUGGER
-#define CATCH_BREAK_INTO_DEBUGGER() Catch::isTrue( true );
+#define CATCH_BREAK_INTO_DEBUGGER() Catch::alwaysTrue();
 #endif
 
 #endif // TWOBLUECUBES_CATCH_DEBUGGER_H_INCLUDED