Update appveyor / Travis-CI.

Based on https://github.com/shlomif/perl6-CI-Gen and
https://github.com/shlomif/ci-gen-framework .

See:

* https://en.wikipedia.org/wiki/Travis_CI

* https://en.wikipedia.org/wiki/Continuous_integration .

.travis.bash

@@ -43,7 +43,7 @@ then
     cpanm --notest Class::XSAccessor Config::IniFiles HTML::Links::Localize
     bash bin/install-git-cmakey-program-system-wide.bash 'git' 'src' 'https://github.com/thewml/website-meta-language.git'
     bash bin/install-git-cmakey-program-system-wide.bash 'git' 'installer' 'https://github.com/thewml/latemp.git'
-    sudo -H `which python3` -m pip install beautifulsoup4 bs4 cookiecutter lxml pycotap vnu_validator WebTest Zenfilter
+    sudo -H `which python3` -m pip install beautifulsoup4 bs4 cookiecutter lxml pycotap vnu_validator Pillow WebTest Zenfilter
     perl bin/my-cookiecutter.pl
     # For various sites
     cpanm --notest HTML::Toc XML::Feed