- added config method that excepts objects with props:
   - valueKey (default: keyValue)
   - attrKey (default: keyAttributes)
   - attrPrefix (default: @)
   - lowerCaseTags (default: true)
   - trueIsEmpty (default: true)
   - autoDate (default: true)
- converting tag and attributes to lower case is optional
- optional converting boolean true to empty tag
- auto Date parsing is optional