Several (quite important) fixes

[igorsantos07]

[1] Upgrading computed properties to comply with Ember updates

That piece of code was causing a deprecation warning. See http://emberjs.com/blog/2015/05/13/ember-1-12-released.html#toc_new-computed-syntax

[2] Fixing big problem with custom-named belongsTo relations

A relationship such as problem: DS.belongsTo('item', { async: true }) was being stored with className: 'problem' instead of 'item'.

[3] Fixing id getter on hasMany relations

It seems the id property is not an attribute from the child relation.

[mixonic]

@igorsantos07 can you squash this to a single commit?

I also believe that the change from snapshot.attr('id') to snapshot.id may not be backwards compatible. Can you confirm what version of ember-data added reading the id directly off the snapshot? That may need to become the version of Ember-Data a next release supports.

[igorsantos07]

@mixonic I haven't worked on my project for a while, hence this is stopped.
I'll take a look if getAttr() would solve the id issue in any way. I'm not sure anymore why I changed from attr('id') in the first place - and I'm not sure it would be easy to discover when id started to be available :(

Besides that, do you want me to squash all commits into one? I may try but I think some of them are related to different issues, and thus should be separated.

[mixonic]

@igorsantos07 the merge commits etc should atleast go away. Please squash as you see fit!