Create Finnish translation for Mastodon

The Mastodon mascot was previously anchored to the bottom, and that was since broken. This restores that behaviour!

It also disables the double-scrollbar behaviour that was caused by this area allowing overflow-y in addition to its parent doing so.

button would be displayed in account lists for unloaded relationships

refreshes on navigation

word-break:break-all is a surefire way to break things. It should be set
to normal.
This merge just set it back to what it should be.
Tested on Firefox 52.0.2 and Chrome 56.0.2924.87 with no detected
errors.

admin UI

I was informed that the current warning if you @ a remote server in a private post is inadequate. These are suggested changes to better inform users.

Thanks garg

Privacy descriptions were very difficult to reason. This is the minimal level of color contrast to be WCAG AA compliant.

Descriptions of differences between scope are more clear