add viewport jquery library
add elastic search limit and offset support
add ajax loading of more search results
add old videos sql
minimize owl
improve search results count label
add static error 500 page
nginx replaces 500 response with static e500 page
improve runtime e500
update .gitignore
merge ents

https://github.com/greenwoodents/khanova-skola/compare/39903d0...341ed18
fix duration template helper