o.a.l.queryparser.flexible.standard.StandardQueryParser cleanup

* Removed unused, but confusing code (CONJ_AND == CONJ_OR == 2 ???). Unfortunately, the code generated by JavaCC from the updated StandardSyntaxParser.jj differs in more places than necessary.
* Replaced Vector by List/ArrayList.
* Corrected the javadoc for StandardQueryParser.setLowercaseExpandedTerms

ant test in the queryparser directory runs successfully