Scroll post-item-view into view

Closes #3998
- Scroll the active post into view on page load
- If the active post changes and the newly active post is offscreen, scroll it into the middle of the screen
Update downsize node module. Small test updates.

issue #4017
- downsize 0.0.5 -> 0.0.8
- downsize is now better at punctuation, update {{content}} and {{excerpt}} tests appropriately.

Conflicts:
	package.json
Change user deletion warning to be more explicit.

Issue #4583
- If a user has posts, show the count in the deletion warning.
Swap button-order on modal dialogs

Issue #4583

- Delete button should be on the right, cancel on the left, for all modal dialogs.
Fix active menu state on settings navigation

closes #4622
- unfocus ActivatingListItem link when clicked
Add support for zip import

fixes #4607

- moves file checks from db and upload API endpoints to api utils
- adds code to accept and then extract a zip and pull out a JSON file
- zip handling requires a lot of dependencies - this needs a good refactor
Tag Cover Images

Closes #4506

Works just like the Post Cover Images (and uses the same component)
Tiny changes to the component ensures that we can reuse it across Ghost
Merge pull request #4623 from vikhyat/unfocus-nav

Fix active menu state on settings navigation
Merge pull request #4621 from graphiclunarkid/issue4583

Swap button order on deleter-user modal
Merge pull request #4626 from ErisDS/issue-4607

Add support for zip import
Labs page bug fixes

- clear import errors on new attempt
- clear posts and tags from store after delete all
Password change MU

closes #4624
- added user_id to password reset request
- hide old password field
- updated changePassword method to check permissions
- updated changePassword method to work without oldPassword
- fixed bug for errors shown as [Object object]
Merge pull request #4630 from ErisDS/labs-bugfixes

Labs page bug fixes
Merge pull request #4628 from sebgie/issue#4624

Password change MU
Merge pull request #4619 from jaswilli/issue-4583

Change user deletion warning to be more explicit.
Merge pull request #4613 from felixrieseberg/iss4506-2

Tag Cover Images
Modal spacing & warning colour

Closes #4583

- Adds a `.red` class (used to make the post count red)
- Adds a little spacing under the modal header to things arent bunched up
Autosave for whitespace-only titles

closes #4625
- trim white space form `titleScratch` to enable autosave for
whitespace-only titles
Merge pull request #4632 from PaulAdamDavis/modal-colour-spacing

Modal spacing & warning colour
Merge pull request #4635 from ikhattab/fix-autosave-whitespace-title

Autosave for whitespace-only titles