Parser option to limit split parts to max arity 

Related to #258 and #362: 

This parser option should make the below test pass:
```
def cli = new CliBuilder()
cli.b(args: 2, valueSeparator: ',', 'arguments')
options = cli.parse(['-b1,2,3'])

assert options.bs == ['1', '2']
       |       |  |
       |       |  false
       |       ['1', '2,3']
       groovy.util.OptionAccessor@ba2f4ec
```