Merge pull request #31 from SeoFood/master

simplexml_load_file needs a file.

Author: Vinai

src/MagentoHackathon/Composer/Magento/PackageXmlParser.php

@@ -108,7 +108,7 @@ protected function _parseMappings()
  $map = array();
 
  /** @var $package SimpleXMLElement */
- $package = simplexml_load_file($this->getFile());
+ $package = simplexml_load_file($this->getFile()->getPathname());
  if (isset($package)) {
  foreach ($package->xpath('//contents/target') as $target) {
  try {