Feature request: allow notifications of historical documents

[kelockhart]

Use case: in some cases, users want to be notified when we add papers to the database that match their query terms and are not necessarily recently published.

Current behavior: we automatically add entdate:[XX TO YY] pubdate:[YYYY-00 TO *] to a given query, where YYYY is the current year, as we assume that users only want notifications of recent papers.

Proposed fix: in the general-type query notification setup (from the search results page), add a flag to allow users to enable historical results (or, conversely, a flag to only return new papers; this would be set by default). If historical results are allowed, do not add pubdate:[YYYY-00 TO *] automatically to the query when generating notifications.