new lines after each call
HT-Numbers must be part of data
unify with html.html
refactoring DigitoolDigitalEntityBuilder

- DigitalEntityBuilderInterface
- EdowebDigitalEntityBuilder
- EllinetDigitalEntityBuilder
- XmlUtils
edoweb-sync, ellinet-sync, regal-sync, refactored

- volumes and issues are supported
- DigitalEntity clean up (not completely)
- EdowebDigitalEntityBuilder rewritten
- ellinet-sync uses the EdowebDigitalEntityBuilder