Updated icon font
Load all tabs saved in configuration directory

In addition to tab list saved in configuration, all tab files for tabs
that are not in the list are loaded.
ItemSync: Custom file types (set format and icon)
Disable/lock browser if tab file cannot be opened
ItemSync: Add proper header to data file

Old tabs need to be removed and re-added (tab is otherwise locked).
Use proper editor in items

Some plugins should use existing editor of item if available --
otherwise it shouldn't create its own.

Disable editor if it doesn't make sense for item.
ItemSync: Properly update item data if configuration changed
Hide dummy item if there is no text to display
ItemSync: Splitter for tables in configuration