Add 'id' to post sort fields. So there is no longer equally sorted posts.

closes #4648
- Add id to order by fields on posts API
- Order by id on posts controller
Optimize model class methods

No Issue
- Reorder promise chains to defer database queries until they
  are needed.
- Execute database queries that are not dependent on each other in
  parallel instead of sequentially.
- Reduce the number of variables used to hold state across multiple
  promise blocks.
- Do not go async unless necessary.
Update dependencies

No Issue
- cheerio@0.18.0
- compression@1.2.2
- express@4.10.6
- morgan@1.5.0
- node-uuid@1.4.2
- request@2.51.0
- sqlite3@3.0.4
- validator@3.26.0
- grunt-jscs@1.0.0
Merge pull request #4684 from jaswilli/deps

Update dependencies
Merge pull request #4674 from delgermurun/post-sort

Add 'id' to post sort fields. So there is no longer equally sorted posts.
Merge pull request #4670 from jaswilli/model-opt

Optimize model class methods
Merge branch 'master' of https://github.com/TryGhost/Ghost

Conflicts:
	core/server/models/user.js
	package.json