Code review comment for lp:~deryck/lazr-js/multiline-fixed-width-412574

This branch is a fix for Bug #412574. This removes the fixed widths in
CSS for the multi-line editor. You can now have fluid multi-line
editors or fixed width. If no width is specified in the editor's config
object, the widget is fluid.

The examples have been updated to reflect both a fluid and fixed version
of multi-line editing. The documentation around the examples has been
updated, too.

I also did a drive-by fix to better line up the submit and cancel
buttons with the edit icon.

This is a branch that Danny Tamez and I were working on together at the
lazr-js sprint.