Update to 1.912

Upstream changes:
1.912    2018-12-31 13:46:22-05:00 America/New_York
        - include the doc updates from 1.911 changelog, oops!

1.911    2018-12-22 11:30:28-05:00 America/New_York
        - just like 1.910, but with doc updates and undeprecation by Jim Brandt

1.910    2018-12-17 21:27:28-05:00 America/New_York (TRIAL RELEASE)
        - update parsing to mitigate pathological cases (thanks, sunnavy!)

(wen)