Returns a site relative HTTP path from a partial path starting out with a ~. Same syntax that ASP.Net internally supports but this method can be used outside of the Page framework.
Works like Control.ResolveUrl including support for ~ syntax but returns an absolute URL.
Returns the path as relative of current location (ie. ./link.htm) if HttpContext is not available. Note that this may result in some scenarios where an invalid URL is returned if HttpContext is not present, but it allows for test scenarios.