Parsing image URLs

[BrianS]

When dompdf parses a URL it takes the URL as supplied. This is the desired and expected behavior, but I have found one case where some cleaning up may be warranted. If the user supplies a URL to a file and inadvertently includes a space at the end of the URL the image will not be processed. This is, of course, a mistake on the part of the user and I am loath to include any functionality that could have adverse side affect. But trimming spaces from the beginning and end of any image URL may be safe.

Any thoughts?