[Templates] Catching missing object methods

[Andy Wardley]

Tom Insam wrote:
> Yesterday I got bitten really badly by something I think I can best 
> illustrate with a test case.

Hi Tom,

This looks like the same bug that we've just fixed in 2.14a

* Changed Template::Stash to be a little more strict about what it
  considers a failed method call.  This allows exception thrown within
  called methods to be propagated correctly rather than being ignored
  as undefined method.  Thanks to Dave Howorth for reporting the
  problem and providing a fix.  Also ported to the Template::Stash::XS
  module.

  http://tt2.org/pipermail/templates/2005-April/007375.html

However, looking over your patch and ours, I can see that we don't go
as far as looking for the "...via package Whatever", and we clearly 
should.

So I've merged your changes in.  Many thanks to both you and Stig.

A