StatusBar UI-updating code probably doesn't belong in EditorManager

[peterflynn]

In Sprint 15 we added about 130 lines of code to EditorManager that maintains the various status labels in the status bar (cursor pos, current syntax mode, tab settings, etc.). EditorManager is a low-level core module and probably shouldn't be acting as the view/controller layer for the status bar.

StatusBar.js is probably also not the right place, since it seems to be intended more as a generic container that various modules can plug into. We may want to create a new module, e.g. EditorStatus or EditorStatusBar, to contain this code.

[peterflynn]

p.s. We've already seen some intertangling of core Editor-management code with status bar UI-updating code as a result of this -- witness the refresh() calls that snuck into _onFocusedEditorChange(), which are probably contributing to the scrolling issue noted in #1864.

[redmunds]

We may also want to move StatusBar.html to the htmlContent folder.

[pthiess]

Reviewed and assigned to @redmunds

[njx]

This didn't have a priority--adding "low priority" (though I could be convinced it's medium priority, since we'd like to avoid messy dependencies).

[peterflynn]

I have a fix up for this in pull #3061

[jbalsas]

Fix merged. Closing and adding milestone Sprint22.