remove capture info from the server
function () {
			var self = this;
			console.log('clearing...');
			var req = get_req();
			req.onreadystatechange = function clear_state_response () {
				if (req.readyState === 4) {
					htracr.ui.clear();
				}
			};
			req.open("POST", "/clear", true);
			req.send("");
			return false;
		}