XLSSchemaReader, XLSInstanceReader and XLSInstanceWriter test cases.

Also added test data.

Change-Id: I6a2d865a01d81c2d4b4bd3be080579de09d8e28c
Reviewed-on: http://gerrit.esdi-community.eu/3111
Tested-by: Jenkins <sitemple@igd.fraunhofer.de>
Reviewed-by: Simon Templer <simon.templer@igd.fraunhofer.de>