Use a library that supports XML 1.1 for parsing ADOxx meta-models

The currently used library (or configuration thereof) for handling XML only supports XML 1.0. The ADOxx meta-model descriptions are however created as XML 1.1 syntax. This CAN cause problems in the current state. From the README:
The exported XML also contains AdoScript code which has been specified in the ADOxx library as values of attributes (e.g. library's External coupling, instance attributes of type PROGRAMCALL etc.), but not the files in the database. The exported AdoScript code uses a custom XML structure where commands are encoded as a mix of XML elements and XML attributes. This can lead to the characters [] being used as part of an XML attribute identifier, e.g. when having code like SETL myVar[1]:("a") in an attribute of type PROGRAMCALL. These characters are however not allowed in XML 1.0. Since the meta-model transformation doesn't translate any AdoScript this problem can be solved by using an XML 1.0 syntax check tool and removing any problematic characters.

Switching to a library that support processing of XML 1.1 could be helpful. Could be coupled with issue #1.