Allow template filename to be given directly

[Wichert Akkerman]

It would be nice if it was possible to pass in a full template filename directly: grok.template("path/view.html"). I envision the behaviour to be something like this:

 * if the given filename has an extension use that
 * if no extension was given do the usual automatic detection
 * if a path is given, use that
 * if no path is given use the default path

[Jan Wijbrand Kolman (janwijbrand)]

i think we can put this to won't fix as the template = TemplateFile('path to file name') pattern is officially supported for a while now. the issue never got updated though.