Merged existing bitmapper-toolbar with 'bar' element. New/Open/Save/Save
As options moved to menu. Filename moved next to app name. Undo/Redo
buttons moved to right of new toolbar. Status messages now displayed as
toast.

BUG=https://github.com/jackhou-chromium/bitmapper/issues/17
R=mgiuca@chromium.org, tapted@chromium.org

Review URL: https://codereview.appspot.com/187000043