Keep aspect ratio for Emfield Image

The formatters for Emfield's image_ncck didn't deal with keeping apsect ratio of the embed images. This is realized by leaving 'width' or 'height' when it is set to 0. When this was the case in the Emfield image settings, lightbox-thumb-images where not displayed, because their height or width had been set to 0.

Changing the following lines in theme_lightbox2_image_ncck fixes this issue:
@line 1869:

    $attributes = array();
-    $attributes['width'] = $width;
-    $attributes['height'] = $height;
+    if ($width) {$attributes['width'] = $width;}
+    if ($height) {$attributes['height'] = $height;}
    $target = variable_get('lightbox2_node_link_target', FALSE);

I can't provide a patch file at the moment, if you need on, please says so, and I'll upload one, when I'm back at home.