Travis CI continuous integration

+ Add .travis.yml script to define the Travis CI build process.
+ Add setup.php to be used (as symlink) by Travis CI builds.
+ Change submodule to use https instead of ssh, because Travis CI does not have keys so https is just easier.
+ Fixes to setup.php-dist to make things work in less fully-fledged environments.
+ Remove static inclusion of Autoload.php from unit tests.
+ Specify `__CA_BASE_DIR__` in setup-tests.php.
+ Add some comments to setup-tests.php.

You will want ?w=1 to look at this PR :-)