The new selection model in xterm.js doesn't allow inverting colors
right now so piggyback on selection.background. Ideally the terminal
would have its own selection key since it has a terminal.background,
but this is hopefully just temporary until selection color inverting
is done upstream.

Fixes #28389

Part of #27096

Fixes #23621

Fixes #24735

Fixes #24335

Part of #22900

Part of #23522

Fixes #22413

Fixes #21226

Fixes #19204

Fixes #7541

Part of #7321

Fixes #19204

Fixes #10528

Fixes #17976

Fixes #18216

Fixes #17138

Fixes #13554

This would only happen when the viewport was not filled

Part of #13229

Fixes #12038

This reverts commit 8bd60949.

It's taking up space when it has focus which breaks the terminal's position. This
only seems to happen on Mac for some reason.

Fixes #12038

Fixes issue of change terminal line-height breaking scrolling
Fixes #9822

Fixes #6602

Going to hold off on this until sourcelair/xterm.js#224 is merged.

This reverts commit 0a5a071c.

Fixes #10100

Part of #9747

Fixes #9800

Terminal.element is focused when text is focused in the terminal, the cursor
should be styled as such.

Part of #9704

When ctrl+m is pressed (only use default keybinding for now), tab will not be
passed to the pty and instead will propogate up and shift focus.

Part of #6731

Currently using the xterm.js PR branch

Fixes #7045