- 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!
Some files had include guards that didn't match the file name, and
others were missing the include guards entirely.
Standardized this so that every include file has an include guard, and
all the guards are of the form TWOBLUECUBES_<FILENAME>_<EXT>_INCLUDED