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
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
Adds complete url for Sitemap in robots.txt

closes #4589

- Adds {{blog-url}} to robots.txt
- Replaces {{blog-url}} with blog.url from config
Merge pull request #4639 from cobbspur/robots

Adds complete url for Sitemap in robots.txt
Fixes sitemap image errors

closes #4591

- switches to using author cover image
- adds a protocol of http if using a protocol relative url
Merge pull request #4552 from zethraeus/master

Update downsize node module. Small test updates.
Merge pull request #4346 from novaugust/scroll-posts

Scroll post-item-view into view
Merge pull request #4636 from cobbspur/sitemap

Fixes sitemap image errors
Test update to handle downsize improvements

no-issue

- downsize is now better at white space and punctuation