Fix parse error thrown in PHP5.5+

When running composer update the file generated by AutoloadGenerator was
not able to be parsed by php due to a require statement inside the foreach
loop.

The fix is to make the statement work the same as the
autoload_namespaces.php require is done.

Issue occured using the following php versions

PHP 5.5.1-2+debphp.org~precise+2
PHP 5.5.3-1+debphp.org~precise+2
Fix file layout in unit tests

Changes made in previious commit made the output of the file change,
which in turn broke the unit tests. This commit updates the fixtures to
match the new output.
Fix parsing of trunk in SvnDriver, fixes composer/satis#88
Merge pull request #2221 from Alan01252/fix-unexpectedas

Fix parse error thrown in PHP5.5+
Make sure directories we are downloading to are empty

We already clear them on error anyway and usually they should be
empty, but just to be safe.
Correct FileDownloaderTest for invalid checksum