Merge branch 'case_insensitive_search' into 'master'

Case-insensitive search

See merge request !109

docs.it4i/snippets/modules_matrix_search.md

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.slim.min.js" integrity="sha256-/SIrNqv8h6QGKDuNoLGA4iret+kyesCkHGzVUUV0shc=" crossorigin="anonymous"></script>
 <script>
+// override to case insensitive search
+$.expr[":"].contains = $.expr.createPseudo(function(arg) {
+    return function( elem ) {
+        return $(elem).text().toUpperCase().indexOf(arg.toUpperCase()) >= 0;
+    };
+});
 $("#searchInput").keyup(function () {
     //split the current value of searchInput
     var data = this.value.split(" ");