Started working on the custom speech api

I've started implementing the custom speech api.

Unfortunately the project I've been working on most likely wont use this anymore but I figure you might want this source code anyway.

It may seem that there are a lot changes here. Mostly I just made the quotation marks consistent throughout the JS file.

Something I've found wierd about this API is that you require a different access token for the custom speech and regular speech. This might become a consideration going forward cause currently you'd be instantiating two instances of watson-js in order to use functionality. It might be good to save the access token per scope.