appendto/amplify — pull request #57 by duereg (2012-05-11 07:40:34+00:00)
Title: Passing an undefined topic to the pub/sub methods should cause an Error

## Current Behavior

* publish: _No Error_
* subscribe: __Error__ _Cannot call method 'split' of undefined_
* unsubscribe: _No Error_

## Proposed Behavior

I am proposing all three methods throw an appropriate error when passed either null or undefined

* publish: __Error__ _You must provide a valid topic to publish to subscriptions._
* subscribe: __Error__ _You must provide a valid topic to create a subscription._
* unsubscribe: __Error__ _You must provide a valid topic to remove a subscription._