fileset-utils: normalized some URIs and added glob support to fileset-filter hrefs

### px:fileset-add-entry
- normalized input href
- if the file already exists in the fileset; delete the existing entry

### px:fileset-filter
- support for the glob characters * and ? in the href option

### px:fileset-load
- normalized base URIs of in-memory documents

### mediatype-utils
- removed a log statement