Enabled passing in helpers and partials to Mustache views.

[iamnoah]

Nice for AMD and avoiding globals. Compatible with standard Mustache/Handlebars semantics.

Usage:

    renderer(data,{
      helpers: {
         cap: function(s) { return s.toUpperCase(); }
      },
      partials: {
         partial: anotherRenderer
      }
    });

Partials can be the view function returned by steal, a new can.Mustache, or a plain old function that takes data and returns a string.

[iamnoah]

The Handlebars semantics are:

template(context, {helpers: helpers, partials: partials, data: data})

So this makes the can.Mustache renderers interchangeable with Handlebars functions, which makes migration easier.

[daffl]

I think helpers have been added in aeb3448. I do agree however, that it should use handlebars semantics. @moschel Input?

[daffl]

People! Talk to me :)

[moschel]

I like this request for a different reason, the fact that it makes helpers local vs global. The fact that it follows handlebars semantics is icing on the cake and kills 2 birds with one stone. I made the original API work as well (passing helpers in as the optional 3rd argument) for consistency with EJS. I also added another test to prove that this removes the global helpers issue.

[moschel]

merged with master and added more tests in #260