Update to 0.17

Upstream changes:
0.17      2017-06-27 14:03:47+01:00 Europe/London

0.16      2017-06-25 20:30:15+01:00 Europe/London (TRIAL RELEASE)
    - Add missing testing prereqs  (github pr#9 paultcochrane)
    - Extend list of Perls in Travis config  (github pr#10 paultcochrane)
    - Avoid pod-spell test failure from ABSTRACT text  (github pr#11 paultcochrane)
    - Minor documentation fixes  (github pr#12 paultcochrane)
    - Purge trailing whitespace in Travis config    (github pr#13 paultcochrane)
    - Fix perlcritic issues  (github pr#14 paultcochrane)
    - Fix stale URLs  (github pr#15 paultcochrane)
    - Remove invalid end tags for empty elements (RT120384)
      (github pr#16 paultcochrane)
    - Rework Dist::Zilla config to be more portable

(wen)