add composer and fix unit tests

[gluneau]

Install composer if you don't already have it:
sudo apt-get install composer

Once in the repo's directory, do:
composer install

This will install the phpunit test suite.
You can then test all tests using this command:
vendor/phpunit/phpunit/phpunit tests

Or if you want to test one at a time, do this:
vendor/phpunit/phpunit/phpunit UnitTest tests/sponsors_Test.php

Long live PHP, Steem and Utopian.io