Make CodeMirror object accessible.

[scottfalkingham]

This surfaces the CodeMirror object as a global variable so it is available to perform advanced functions such as CodeMirror.defineMode, which was impossible previously.

For more information see this SimpleMDE issue.

[axe312ger]

Why not require CodeMirror on your own? You just inject the require of this lib into the window object.

[Ionaru]

I am also not sure about this change. What is the use-case for using the editor's CodeMirror package instead of importing your own? That should be easy enough to keep in sync.

Say the editor would at some point use tree-shaking to make the dist package smaller then it wouldn't even be the full CodeMirror package that is exposed.

[coconutpalm]

Maybe a better solution would be for Easy MDE to use window.CodeMirror if it exists? Then if clients want to supply their own CodeMirror (perhaps with an expanded set of modules included), we would just pick that up. Otherwise, we would do what we do right now.

[A-312]

@Ionaru Can you explain your message ? I also want to make a custom highlighter