Conform to PSR-2, add Composer/PHPUnit configs

I've removed the two new exercises and squashed this into one commit, this PR reformat to PSR-2 standards.

The classes are now autoloaded with the phpunit.xml and composer.json provided. (This is done using Composer's autoloader)

The make file has been updated so only the tests are rewritten to the tmp dir and they are modified on the way to not skip tests and to require in the classes needed so it doesn't require an autoloader. (I'm sure this can be done in a nicer way as this is a bit hacky)

I am unsure how the CLI tool provides files, is it possible that when fetching PHP exercises that the composer.json & phpunit.xml are provided as well as perhaps a language specific README? That way when a user came to do some PHP exercises they would have a standard quick and easy way to get PHPUnit and the tests running. e.g:

    % curl -sS https://getcomposer.org/installer | php
    % php composer.phar install
    % php vendor/bin/phpunit [Exercise]

Let me know any problems/improvements and I'll work on it.

So instead of marking the tests as skipped give them a group annotation such as @group skipped and ask the user to remove the annotation rather than the $this->markTestSkipped line?

So the user would run tests with

    $ php vendor/bin/phpunit --group-exclude skipped Exercise

The @group comment annotation would be easier/quicker to remove than removing a line inside the test method. I'll make another commit to switch to this method of excluding the other tests.