drupal_get_library() may break JavaScript library path by clobbering it with the library version number

This is one of those "oh... PHP" issues that is so bizarre it's *almost* funny, except it causes lost hours of work trying to figure out what's happening.

The end result is that the "version" string (or the first character of it) replaces the first character of the JS path. So if your library is version "1.0" and your JS path is "sites/all/modules/mymodule/library.js", the path gets clobbered and turns into "1ites/all/modules/mymodule/library.js". Obviously this causes the JS file to not actually get added to the page, as the path is wrong.

This problem only manifests itself when using the "shorthand" library syntax.

To reproduce. Add a library hook such as this to a custom module:

function mymodule_library() {
  $libraries['mylibrary'] = array(
    'title' => 'My Module: My Library',
    'version' => '1.0',
    'js' => array(
      drupal_get_path('module', 'mymodule') . '/mylibrary.js',
    ),
  );

  return $libraries;
}

Then (for simplicity's sake), in hook_init() add your library to the page:

function mymodule_init() {
  drupal_add_library('mymodule', 'mylibrary');
}

You would expect that the path "sites/all/modules/mymodule/mylibrary.js" would be added to the page, but instead "1ites/all/modules/mymodule/mylibrary.js" is. You can change the version number to "2.0" and see that the path becomes "2ites/all/modules/mymodule/mylibrary.js".

This problem stems from this bit of code in drupal_get_library:

        $module_libraries[$key] += array(
          'dependencies' => array(),
          'js' => array(),
          'css' => array(),
        );
        foreach ($module_libraries[$key]['js'] as $file => $options) {
          $module_libraries[$key]['js'][$file]['version'] = $module_libraries[$key]['version'];
        }

If $file is not an array, but a string, then setting "version" actually just replaces the first letter of the string.