Update "dynamic segments" section

Update "dynamic segments" section according to Ember Data transition document, more details at https://github.com/emberjs/data/blob/master/TRANSITION.md

Note: source comments should change accordingly, see https://github.com/emberjs/ember.js/blob/master/packages/ember-routing/lib/system/route.js
Don't recommend preloading in ApplicationRoute#activate

model hooks for all routes run before any of the activate hooks.
Consequently this preload code only runs after all of the
required models are requested.
Merge pull request #784 from elucid/preloading-doc-fix

Preloading in ApplicationRoute#activate doesn't make sense
Merge pull request #771 from potomak/patch-1

Update "dynamic segments" section
clarify meaning of 'model hooks'
Merge pull request #786 from raulbrito/patch-1

clarify meaning of 'model hooks'
Grammar fix
Update "Defining Your Routes" guide to use find calls in ember-data 1.0 beta
Remove trailing whitespace in the "Defining Your Routes" guide
Update displaying-model-data.md

Add a comment line
Added loading spinner to build section
`query` method is no longer available in the store

* The way of triggering the same behavior is using the `findQuery`
  method. See:
  https://github.com/emberjs/data/blob/master/packages/ember-data/lib/system/store.js#L595
Merge pull request #788 from bcardarella/grammar-fix-1

Grammar fix
Merge pull request #789 from balinterdi/update-defining-your-routes-guide-2

Update Defining Your Routes guide
Merge pull request #790 from olbrzym/patch-1

Update displaying-model-data.md
Merge pull request #791 from intuitivepixel/master

Added loading spinner to build section
Merge pull request #792 from iperdomo/master

`query` method is no longer available in the store
nested tabs for builds
merging loading gif