To keep language consistent, three methods were changed in InputOption:
* `InputOption::acceptParameter()` -> `InputOption::acceptValue()`
* `InputOption::isParameterRequired()` -> InputOption::isValueRequired()`
* `InputOption::isParameterOptional()` -> `InputOption::isValueOptional()`
The InputDefinition::asXml() method was also modified to update the `accept_value` and `is_value_required` attributes.