log stop_loading
don't send the same args to a script multiple times
prevent out-of-order execution of async commands; better validation of splash:wait; splash:wait returns "ok" flag
BrowserTab.go callback should be run only once
cleanup: move logic to SplashQWebPage
allow to cancel timers on render errors
TST tests for splash:wait
lua: return ok=nil instead of ok=false
lua: small logging improvement
splash:wait timers are cancelled on errors
fix waiting issues in an example lua endpoints
DOC some docs for scripting
fix cancel_on_error option handling for splash:wait()
TST add more tests for splash:wait(); refactor existing tests.