ENH: turn on paging -- makes search much more responsive!

I did not figure out how to increase number of entries on the page so we could
go to a bit higher number.  Benefit from paging seems to be too massive for search

assets/js/main.js

@@ -190,15 +190,15 @@ function directory(jQuery) {
     // add HOWTO install
     jQuery('#installation').prepend(
         '<P style="margin-top: 0px;">Centralized registry of Jitsi audio-video conference rooms per each poster or software demo of OHBM 2020.</P>' +
-        '<P style="margin-top: 0px;">Just browse or quickly search by words etc.</P>' +
+        '<P style="margin-top: 0px;"><b>We turned on paging, please search by poster number, keywords, names, etc.</b></P>' +
         '<P style="margin-top: 0px;">"Online" counts are approximate and count only people attending through this page.</P>' +
         '<P style="margin-top: 0px;">For every poster there is a dedicated Jitsi room, which would open in a "dedicated" new window/tab.</P>' +
         '<P> More info, sources, issues, PRs:  <a href="https://github.com/datalad-datasets/ohbm2020-posters" target="_github">https://github.com/datalad-datasets/ohbm2020-posters</a>.</p>'
         );
 
     let table = jQuery('#directory').DataTable({
         //async: true,    // async get json
-        paging: false,  // ensure scrolling instead of pages
+        paging: true,  // ensure scrolling instead of pages
         rowId: 'id',
         columns: [ 
           {data: "number", title: "#", width: "5%"},