Use CodeMirror compoundChange to ensure batch operation can be undone

[zanqi]

This is to fix Issue #1957

[RaymondLim]

Your changes do fix the issue in the main editor, but I still can reproduce it in an inliine editor though.

And I found 3 calls to batchOperation -- one from Line Comment and 2 from Move Line Up/Down. Line Comment command does not have the issue even before your changes. So I believe this issue has to do with some selection handling in CodeMirror and probably we won't be able to fix it in Brackets code.

[zanqi]

CodeMirror's batch operation has some weirdness in it due to its operation deferring nature. Need more investigation. Closing.

[peterflynn]

@zanqi: note that the batching logic is changing in CodeMirror v3, which we are hoping to migrate to in the next month or so. It might be simplest to wait until then before working on a fix for this (it might even be fixed for free). @njx can give you more details if you're interested.

[peterflynn]

We wound up merging basically this exact same change after further testing, in #2132. As far as I can tell it does fix #1957 -- @zanqi, were you seeing cases where this change didn't fix it?

[zanqi]

Looks good. Tested in main editor and inline editor for JavaScript, undo successfully.