Support Joins on the fly

[esatterwhite]

Currently if you want to include related data you need to specify the join on the resource definition

Resrouce.extend({
   options:{
      queryset:Model.find().getJoin({...})
   }
})

If this isn't done, then filters across relations won't work. If there is a way to check & fetch if the join wasn't initially defined, that would be desirable.

I was having a problem with getJoin and custom methods on models - in that it didn't work and crashed.