Expose the CodeMirror library object, so static methods like defineExtension can be called on it

[brondsem]

Hi,

This is a very small change to enable more customization of EasyMDE/CodeMirror, like allowing addons to be used (fixes [#188] then). Otherwise there is no way to run CodeMirror static methods.

It is very similar to [#76] but more cautious (not setting global window.CodeMirror).
In that pull request it was suggested to just package another copy of CodeMirror, but that doesn't work because running CodeMirror.defineExtension(...) would only affect the separate copy and not the one used by EasyMDE.

Steps to enable a CodeMirror addon would be:

• include easymde.min.js on page as usual
• EasyMDE.CodeMirror.defineExtension(...)
• or if you want to use a standard addon: window.CodeMirror = EasyMDE.CodeMirror and include the addon .js file

[Ionaru]

I'm tempted to raise the same argument I did back then: The editor cannot guarantee that the entire unchanged CodeMirror library will be included with it. With this change, you, and others, will assume that it does by using methods from that library.

I think the solution offered by @coconutpalm in his comment on PR #76 is better.

[brondsem]

Ok, I've added a commit that does that.

Standard codemirror.js is currently 389K (129K on gzip) so I think there's still a case for avoiding 2 instances of the library on a page. Exposing the internal instance seems simple (if folks use it at their own risk). Maybe another option would be an EasyMDE build that doesn't include codemirror.

[Ionaru]

I'm asuming 129K is unminified and can be reduced further because the EasyMDE package is only 95.7K.

[brondsem]

Yes, that's lib/codemirror.js straight from CodeMirror's release zip - they don't provide a minified version. Minified I get it at 168K; 66K gzipped.

[Ionaru]

This isn't needed anymore, right?

[brondsem]

Not for your preferred approach, correct. I'd still find it useful to avoid ~66K duplication though.