Replace uses of doc.url with _server.pathToUrl()

[njx]

For #5317. doc.url was an old field that used to get set on the document before we refactored the live dev server management in 1f6b5aa, but there were still a few places referencing it.

[njx]

To @jasonsanjose since he's already looked at this branch :)

[jasonsanjose]

Confirmed this fixes the issue with .js files and the out-of-sync status.

#5317 also mentions this is broken for HTML-files from a user server. That bug still exists here. The offending code is in LiveDevelopment _docIsOutOfSync. I have a fix:

    function _docIsOutOfSync(doc) {
        var docClass    = _classForDocument(doc),
            liveDoc     = _server && _server.get(doc.file.fullPath),
            isLiveEditingEnabled = liveDoc && liveDoc.isLiveEditingEnabled();

        return doc.isDirty && !isLiveEditingEnabled;
    }

[jasonsanjose]

@njx review complete

[njx]

Ah, I missed that other part of the bug. I'll look at your proposed fix.

[njx]

I added your fix and added a few unit tests to make sure the dirty dot does show up in the JS case and doesn't show up in the live HTML/CSS cases. I didn't add a test for the user-server-HTML case since I wasn't sure of a good way to do that, and it doesn't seem like as critical a case anyway.

[njx]

Ready for re-review.

[jasonsanjose]

Looks good. Merging.