overshadow requirement for remote-lookup

untested, my vagrant is bugged again, submitted at gargron's request

work flawlessly was a nightmare). WARNING: This commit makes the web UI connect to the streaming API instead
of ActionCable like before. This means that if you are upgrading, you should set that up beforehand.

sounds complex, but really it just reorganizes the posting options and
adds a seperator line

they have been loaded and favourited/reblogged from another source

Since the status JSON returned from public/hashtag streams does not
contain favourited/reblogged attributes, merging them should not
override existing ones.

redis-backed "mentions" timeline as redundant (given notifications)

Changing the way the background image is positioned and the box is sized should fix problems with the text overlapping the image on mobile browsers and Edge.

nested inside a common parent (<Account>), instead they all embed <HeaderContainer />

the public timeline has been using

Currently we have the problem where the follow request button is missing
from the Follow request tab. This means that when you visit that tab you
either have to press the back button in the browser or re-enter the home
page, which breaks the app flow.

This will resolve that issue by adding a new back button to that tab,
in the same way that the public timeline, and favourites have.

remove button outlines on-click for retweet, boost, favourite, and reply
buttons

fix ProcessFeedService pushing status into distribution if called a second time
while the first is still running (i.e. when a PuSH comes after a Salmon slap),
fix not running escape on spoiler text before emojify

Currently we have two problems that are resolved by this change.

The first is that we have a dependency on Google Fonts, which means
that should it ever go down, or it have issues we would also have
issues. This will resolve this by moving the dependencies we load from
there to the local server.

The second issue is that Google Fonts is currently returning the
`local()` css font source. This causes a problem where the users browser
fails to fallback to a missing glyph, resulting in many unusual
characters displaying the failure glyph. This will resolve this by
creating a font-family definition that does not use the `local()`
source.

I did not update the error pages with local fonts, they still use the
remote google fonts api, so they're a self contained page that does not
use the asset pipeline.

This resolves tootsuite/mastodon#531 and tootsuite/mastodon#12

for extremely wide monitors

improved how "show more" link looks

Currently, the getting started text fails WCAG standards for color contrast by a lot. Especially on the part overlapping with the elephant graphic which is nearly unreadable even for users with 20|20 vision. This change doesn't fix the elephant overlap but at least makes the text meet AAA WCAG Small Text color contrast standards, making it easier to read.