https://github.com/codemirror/CodeMirror/issues/3237

Closes #3233

Issue #3229

This makes it impossible to change the mode of the editor
and still automatically get appropriate annotations.

Issue #3227

Closes #3222

https://github.com/codemirror/CodeMirror/issues/3219

Issue #3189

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

Fixes https://github.com/codemirror/CodeMirror/issues/3215

Issue #3214

This changes will make the optional space character after ATX style
headers be included within the `cm-formatting` element.

https://msdn.microsoft.com/en-us/library/ms189822.aspx

Closes #3172

Closes #3207

https://github.com/codemirror/CodeMirror/issues/3205

Issue #3204

And change handlebars demo to use it.

It was never standardized and is no longer a reserved word: http://publications.gbdirect.co.uk/c_book/chapter2/keywords_and_identifiers.html

Currently and/or/not in most themes look like normal text because cm-operator doesn't usually get special styling. This patch highlights them as keywords to make them stand out better.