Do not eagerly fetch relations in when finding all posts

fixes #4232
- do not fetch tags and fields relations in post.findAll()
Fix high latency autosave bug in editor.new

Closes #4400
- Added focusCursorAtEnd property to codemirror component, to set the cursor at document end on load. Used for posts that have been edited
- centralized codemirror init code in component
Update PSM Date to be Selectable
Fix invalid image helper URLs when using a subdir.

No Issue
- Strip sub-directory from image paths before passing to
  config.createUrl. Since images are stored with the sub-directory
  and createUrl builds a URL with the sub-directory the result
  would be a URL that contains the sub-directory twice.
Improve validation for user.website

closes #4444
- validate URL without protocol in server and client
- when saving url, add `http://` if the url doesn't have a protocol
Merge pull request #4448 from dbalders/master

Update PSM Date and Time to be Selectable Instead of Text
Merge pull request #4465 from jaswilli/subdir-image-url

Fix invalid image helper URLs when using a subdir.
Merge pull request #4459 from novaugust/slow-save-errors#4400

Fix high latency autosave bug in editor.new
Merge pull request #4436 from mattiascibien/issue-4232

Do not eagerly fetch relations in when finding all posts
Improvements to the permalinks UI

Closes #4454

* Relies on Flexbox more heavily
* Adds JS to simulate how it should work
Merge pull request #4466 from VictorVation/url-validation

Improve validation for user.website
Revert "Update PSM Date and Time to be Selectable Instead of Text"
Merge pull request #4470 from TryGhost/revert-4448-master

Revert "Update PSM Date and Time to be Selectable Instead of Text"
Upgrading Casper to 1.1.2
Fix issue with editor and images

ref #4459

- move initMarkers back to its original home
- add new test that a post with an image can be edited
Merge pull request #4473 from ErisDS/editor-fix

Fix issue with editor and images
Fixing logic for editors deleting themselves

no issue
- no user is allowed to delete their own account
Merge pull request #4474 from ErisDS/profilefix

Fixing logic for editors deleting themselves
Version bump to 0.5.4
Reverting mysql to 2.1.1

- Unfortunately mysql has changed the way it handles the charset setting such that
it now causes encoding issues on many setups where 'utf8' is apparently not the
correct setting.
- We need to revert this upgrade until the issue is fixed or we have a way to handle
it nicely for our users.