Update link_to.js

add description for `disabled` and `disabledWhen` properties for `link-to` handlebar helper.
Removes long-deprecated getPath/setPath
Query params implementation
Merge pull request #3182 from alexspeller/query-params-squashed

Initial QueryParams implementation
Fixed a typo in link-to documentation
Merge pull request #3375 from graup/typo

Fixed a typo in link-to documentation
corrected mistake in Em.computed.equal docs
Merge pull request #3378 from GavinJoyce/master

Corrected mistake in Em.computed.equal docs
Replace crossLink with a markdown link
Merge pull request #3379 from bmac/fix-cross-link

Replace crossLink with a markdown link.
Merge pull request #3344 from c0urg3tt3/patch-4

Update link_to.js
Merge pull request #3350 from trek/remove-getPath-setPath-deprecations

Removes long-deprecated getPath/setPath
[FEATURE em-o] Added `Em.O` (shorthand for `Ember.Object.create`