[Echo API] create XDomainRequest object globally in case of using CORS in IE8-9 browsers
[Harness, fake requests] match api/search requests with the since parameter
[Stream control] destroy item in case of it was considered as unsuitable, destroy temp item in case of its updates in a single response
[Harness, fake XMLHttpRequest] more defensive regexp to match api/search queries
[Tests] get rid of extra spaces when passing predicate "itemsPerPage" into the query
[Strem, tests] rephrase the test case message
[Stream, tests] fix typos
[Stream, tests] rephrase the test case message (another one with the similar logic)
[Stream] add comment to unobvious part
[Canvas] Hide Loading... if there are no apps defined in a Canvas
[Loader, tests] remove debug code
Merge branch 'neurostep/canvas_hide_loading' into rc3.0.21
Merge branch 'neurostep/clear_item_artefacts' into rc3.0.21