Don't duplicate Catch::isDebuggerActive() check many times, do it just once
in CATCH_BREAK_INTO_DEBUGGER() definition and use a separate CATCH_TRAP()
macro for the really platform-dependent part.
- 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!
