StyleRelativePathTransform modification for querystrings

 // blows up if url contains a query string
 //string absoluteToUrl = Path.GetFullPath(Path.Combine(cssFilePath, relativeToCSS));
 // replace with
 
 // this is a path that is relative to the CSS file
string relativeToCSS = match.Groups[2].Value;

//prevent querystring from causing error
var pathAndQuery = relativeToCSS.Split(new[] { '?' }, 2, StringSplitOptions.RemoveEmptyEntries);
var pathOnly = pathAndQuery[0];
var queryOnly = pathAndQuery.Length == 2 ? "?" + pathAndQuery[1] : string.Empty;


// combine the relative path to the cssAbsolute
string absoluteToUrl = Path.GetFullPath(Path.Combine(cssFilePath, pathOnly));

// make this server relative
string serverRelativeUrl = context.HttpContext.RelativeFromAbsolutePath(absoluteToUrl) + queryOnly;