Do not refresh notebookbar when we start in read-only mode for txt and csv

This is a workaround for the bug, when a txt or a csv file was opened,
and there were both the classic menu and the menu of the notebookbar
at the same time at the top of the window. This bug occurred because
regardless of the user's UI mode setting, the read-only mode has the
classic menu. The fix also have a side effect, that is better than
the original symptom. Now when a txt file is opened, and user starts
editing it, the Zotero buttons won't be on the References tab. I
think it's a good trade-off, but FIXME.
Eventually, when we won't have the classic UI mode any more, this
problem would be solved better, for all corner cased (txt. csv, pdf,
read-only shares etc.)

Signed-off-by: Andras Timar <andras.timar@collabora.com>
Change-Id: Ic3f95c02a0b75136a0b8069fa8297ed129b63865

browser/src/control/Control.Zotero.js

@@ -136,7 +136,7 @@ L.Control.Zotero = L.Control.extend({
 	},
 
 	refreshUI: function () {
-		if (this.map.uiManager.notebookbar)
+		if (this.map.uiManager.notebookbar && !this.map._shouldStartReadOnly())
 			this.map.uiManager.refreshNotebookbar();
 		else
 			this.map.uiManager.refreshMenubar();