Potential memory usage improvement for y-js observe.

[kifhan]

While I fork your code, I notice that you set observe to every text file but don't unobserve them.
I'm not sure unobserve them is improve much of memory usage but I add unobserve code for fixing bug on my reply code.

fork of multihack-core

• notice that I put it in the multihack-web for my convenience.
• check the setObserver method
  RemoteManager.prototype.setObserver = function (filePath, targetstr) {...}

How do you think? Is going to change performance or not really effective.

[t-mullen]

Hmm, yeah I should unobserve deleted files. Thanks for pointing this out.

[kifhan]

FYI, I observe the object that only currently opened in editor.
And I do below just before open a file. (on index.js)
FileSystem.getFile(e.path).doc.setValue(self._remote.getContent(e.path))
It works fine for me.