1) if sort param, use it and do no special ; parsing
2) if no sort param, check for ; and extract sort
..but i'm wondering if we want an explicit param indicating that the old
behavior should be supressed -- that way having no sort param can default
to sort on score just like with dismax (and it won't break if the query
happens to have a ; in it).
the 'explicit' parameter would be sending an empty string for 'sort'
In the existing implementation of QueryParsing.parseSort( ):
null, "", and "score" all return a 'null' (default) SortSpec
so, one way to disable ; parsing for all queries would be to add a
default empty parameter for "sort"
