Change autolinked URLs to output nice quotes

ref #4257

- This is a follow on from #4257 where I updated the codestyle.
- We were outputting escaped single quotes when double quotes would be much nicer.
- Changes the HTML output from our markdown conversion (non-breaking change)
- Updated tests to match the new output
Merge pull request #4280 from ErisDS/gfm

Change autolinked URLs to output nice quotes
Cancel pending auto-save if manual save occurs

Closes #4309
Peg ember-template-compiler to 1.7.0

Closes #4310
- Ember-template-compiler introduced a breaking change in
  1.9.0-alpha. We're using it via grunt-ember-templates.
Merge pull request #4313 from jaswilli/issue-4309

Cancel pending auto-save if manual save occurs.
Ensure slug generation has completed prior to save

Refs #4307 Refs #4259
- Make sure that a slug has been generated prior to the first
  save that occurs on a post.
- Wait on in-flight slug generation requests before saving.
Test improvements

refs #4309
- replace waitForResource with waitForSelector to prevent UI timing
issues.
Merge pull request #4314 from sebgie/test

Test improvements
Tag input UX improvements

Closes #4105

- Turns the tag icon white when input is focused.
- Focuses on the tag inout after deleting a tag.

Credit to @novaugust for a PR to this which is rebased into one single commit
Implement popovers
Merge pull request #4308 from jaswilli/slugs-save

Ensure slug generation has completed prior to save
Merge pull request #4287 from PaulAdamDavis/tag-input-ux

Tag input UX improvements
Merge pull request #4213 from PaulAdamDavis/new-popovers

Implement new popovers
Move unrelated editor cover code to the right place

Closes #4106

Moved the `.editor-close` styles to `post-settings-menu.scss`
Merge pull request #4219 from PaulAdamDavis/overlays

Rename right-outlet to settings-menu
Version bump to 0.5.3