Check existence of "ol.ext" before initializing "ol.ext.input" and "ol.ext.imageLoader"#856

Viglino merged 1 commit intoViglino:masterViglino/ol-ext:masterfrom

sanak:fix/check-ol-ext-input-and-imageloadersanak/ol-ext:fix/check-ol-ext-input-and-imageloaderCopy head branch name to clipboard