Outputting attribute and value containing '=' truncates the value (EJS & Mustache)

If an HTML attribute is output using EJS or Mustache, any value that has a '=' in it will be truncated when live binding updates it. This can be observed in the fiddle below:

http://jsfiddle.net/NMvAd/

This is a problem particularly for __src__ since the workaround to avoid an initial 404 (#157) involves outputting `src=` along with the value.

The problem is in [render.js](https://github.com/bitovi/canjs/blob/master/view/render.js#L363), specifically the update function that runs when you are in a tag, but not an attribute.