speedup search page by storing indexes name in settings.

Build some sitemap can take 3G of RAM or more and freeze the browser or tab. Reduce amount of running ajax queries per time and make sure objects will be removed in memory after usage.

Mynij Search: improve performance, build index now in backround, load body text in result is defered

Improve general search performances
Build index will now run in background and popup when build is finished
when result loaded, fetch body text in another task to speedup.

Fix search form also