Only words with 2 or more characters are accepted
Max 200 chars total
Space is used to split words, "" can be used to search for a whole string (not indexed search then)
AND, OR and NOT are prefix words, overruling the default operator
+/|/- equals AND, OR and NOT as operators.
All search words are converted to lowercase.
Tadeja Balažic, 2016
Natalija Jager, 2016
Martina Tomc, 2015