Add missing include_paths.php to phar compiler script.

The phar file being produced by bin/compile (and hosted on psysh.org) is missing a required file:

>PHP Fatal error:  require(): Failed opening required 'phar:///home/josh/tmp/psysh/bin/psysh.phar/vendor/composer/include_paths.php' (include_path='.:/usr/share/php:/usr/share/pear') in phar:///home/josh/tmp/psysh/bin/psysh.phar/vendor/composer/autoload_real.php on line 29

Added missing file to src/Psy/Compiler.php