Grammar incorrectly defined for DataOneOf

[gnu9]

Similar to issue #3
The FSS-Parser requires DataOneOf(...) to enumerate at least two individuals which does not comply with OWL2-FSS, e.g. OWL-EL does allow only singletons.

To fix it, change in
org.semanticweb.elk.owl.parsing.javacc.Owl2FunctionalStyleParser.jj /* 7.4 Enumeration of Literals */
the lines

<DATA_ONE_OF> <OPEN_BRACKET>
		x = literal() { v.add(x); }
		( x = literal() { v.add(x); } )+
<CLOSE_BRACKET>

into

<DATA_ONE_OF> <OPEN_BRACKET>
		( x = literal() { v.add(x); } )+
<CLOSE_BRACKET>