Initial release as BEXIS 2 module

Initial release of the LUI calculation tool as a BEXIS 2 module. It is based on a work done for the former edition of the software which was developed within the Biodiversity Exploratories project (http://www.biodiversity-exploratories.de/). The old edition was called BExIS (be aware of the notation, no number).

The current version provides the same functionality as the first edition.