Typefully Revamp

[linuz90]

We've just acquired Minimal Twitter from @thomaswang 💫

Since it's now part of the Typefully brand, this PR changes old references to Thomas's websites to new pages hosted on typefully.com.

It adds a new "welcome screen" that is shown to users when they install or update the extension.

Finally, it makes small tweaks to the extension UI.

[ghost]

• made small changes to README (centering logo, adding h1, moving description further down).

[ghost]

• Added to main.css. This will fix the misalignment issue at smaller screen sizes of the nav.

/* Remove list label on small screen */
@media only screen and (max-width: 1264px) {
  #mt-listsButtonNode {
    display: none;
  }
}