REVIEW-3457: allow exception to be serialized by just using taskpath as property
support methods with no argument in CommandLineOptionReader
More cleanup on Help for Tasks based on reviews

- REVIEW-3460 add support for enums
- REVIEW-3459 move knowledge from CommandLineTaskConfigurer to CommandLineOptionDescriptor
			  - knowledge bout option parameters
			  - how to apply option on tasks
- REVIEW-3459 - dont support '--flag true' just use '--flag' instead