Create a new character count view on re-render

When ``StoryInfoView`` is re-rendered, recreate the character counter
view.  Without doing this, view is bound to an editor instance that
no longer exists. It would be nice to be able to reuse this view, but
event binding/unbinding on the wysihtml5 editor requires us to track
all of our event handlers so we can unbind them later.  It seems
easier to just create a new view.

Refactor editor element setting and event binding of
``CharacterCountView``.  Pass the event bus object as an argument
to the constructor instead of accessing something global.

Addresses #579
Fix upload progress for FeaturedAssetAddView

Give a min-height for the wrapper element so the upload progress
meter isn't stuck at the top of the element.

Properly bind the upload progress handler so we see the progress
reflected in the meter.

Clear the parent element so the upload progress handler goes away
when the upload is finished.

In an unrelated fix, re-delegate events for ``FeaturedAssetSelectView``
in an ``onShow()`` method so that click events work properly when
the parent view is re-rendered.