Issue #2360

Issue #2305

pressing Ctrl-Space once starts the selection extension mode,
pressing it again cancels that

It was broken and confused.

Make the mode register a list of completable words instead.

Issue #2324

Since it's what you want most of the time, and easy to forget.

Issue #2305

Require explicit turning on of history event merging.

Issue #2305

Per change authored in https://github.com/marijnh/CodeMirror/pull/1979.

Closes #2200

Issue #2281

As screwed up by e1dcbebb

Added a wrapper for js-yaml.js to enable YAML lint support. Followed
json-lint.js pattern. Unfortunately js-yaml.js only shows one error at
a time, but something is better nothing. Checked code with linter and
ran tests. All came back clean.

Issue #2253

add docs that when completions are object they can have a from: and to:
that will be used by pick.

Make sidebar in manual scrollable for small screen especially usefull
when `Programming API` is unfolded

seem to look nice on Chrome and Firefox Osx, (scrollbar do not appear,
except when scrolling on Chrome) but should maybe be tested on linux.

Closes #2200

Stop ctrl-a from causing the doc to scroll all the way down.

Issue #1968
Issue #1936