Issue #3974

Even if we don't use promise internally, check for the existence of
`.then` attributes on the return results of a hinting function, and if
so assume it is a promise.

Internally also convert all hinters to use the asynchronous interface
for consistency and simplification of code paths.

Closes #3971

Closes #3791

When enabled, and the annotatescrollbar addon is loaded, matches will
be shown on the scrollbar.

Issue #3682

Closes #3569

Issue #3586

Issue #3548

Fixes #3449

Issue #3423

... and export (via defineExtension) a method to explicitly trigger
linting from user code.

Issue #3337
Issue #3338

Spent quite a while perfecting this (IMO), but a lot of people seem to
really like it. Hope you do too.

Issue #3320

https://github.com/codemirror/CodeMirror/pull/3212

Closes #3159

Issue #3053

See http://discuss.codemirror.net/t/simple-mode-and-anchored-regexp/88/4

This file was taken from
https://github.com/wisenomad/zenburn-lighttable-theme with a few
modifications to make it work in CodeMirror

Allows convenient showing of panels (DOM nodes) above or
below an editor, automatically shrinking the editor to make
space.