#581: rose macro - add command line trigger state validation

This adds a proper "validate" method to the trigger macro. It now reports settings with wrong states when called from something like `rose macro -V`.

This closes #581. #581 was also a code-consolidation issue - unfortunately, the use case for rose edit and rose macro reporting of errors is quite different (see [config editor ignored mechanics](http://metomi.github.io/rose/doc/rose-configuration-metadata.html#appendix-ignored-config-edit)), and the part of the code in the config editor that handles this is not too bad - it is complicated, but it does a lot and is reasonably well documented.