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/)
I've wanted to add test descriptions for a while, but (1) we would probably just title it "description" and (2) these will disappear the next time tests get updated in Scaffold (not that it happens a lot for Google Scholar).

To do this right, we should add test description handling in Scaffold (doesn't seem like it would require other changes in Zotero, though I haven't looked closely). Feel free to submit a patch for that if you're interested. Otherwise, this probably won't happen for a few months.

In the mean time, please remove these,