ARQGRA-294, ARQGRA-296: GrapheneElement and isPresent() method introduced
ARQGRA-279: support for search context in waiting fluent API with By locators
ARQGRA-304: added interceptor for handling staleness to list of elements
ARQGRA-274: initialize XHR object in XHRInterceptor constructor with initial values
ARQGRA-300, ARQGRA-275: Guards - reimplement timeout-wrappers defensively + introduced filters
ARQGRA-306: exposed RequestGuard#setMaximumCallbackTimeout(int)
ARQGRA-299: functional tests rewritten to use Jetty container