Get a more-precise Decided Date for cases

Added logic for scrapeCase(...)/getDate(...) to get and save a more
precise Decided Date than what is available in the citelet (if the logic
can find one).  Added test case descriptions for all test cases.  Added
six test cases specifically for testing the added logic.

Also included comment about how the code did and still does fail for a
specific case.  Included link to Zotero Forum post where this was
reported.
(https://forums.zotero.org/discussion/44849/zotero-wont-save-google-scholar-case-but-no-error-report-id-949790485/)