Log Message:
Update to 1.20

Upstream changes:
Release 1.20 - 6 July 2015
 - Document setting PerlSwitches for mod_perl (jpsalvesen) (github 128).

Release 1.19 - 5 July 2015
 - Get things working with 5.22.0.
 - Test against 5.23.0.
 - Remove dependency on Test::Warn.