get validation to run correctly on nested args
at least put some failing / pending tests in place
add tests to ensure that @Required gets correct defaults w/ nesting, and repeated field names
fix valueAsString for a bunch of parsers
Merge pull request #29 from quantifind/fix_nested_validation

get validation to run correctly on nested args
Merge pull request #30 from quantifind/parser_string_value

Parser valuseAsString implementation and tests
Merge branch 'master' into karthik/file-exists-validation

Conflicts:
	core/src/test/scala/com/quantifind/sumac/ValidationSuite.scala