The RegexpMapper changes filenames according to a pattern defined
            by a regular expression. This is the most powerful mapper and you should be able to use
            it for every possible application.
Table F.10: The regexp mapper can take the following extra attributes.
| Name | Type | Description | Default | Required | 
|---|---|---|---|---|
| handledirsep | String | If this is specified, the mapper will ignore the difference between the normal directory separator characters - \ and /. This attribute is useful for cross-platform build files. | false | No | 
| casesensitive | Boolean | If this is false, the mapper will ignore case when matching the glob pattern. | true | No |