Creating new /update URL to replace /action.
Pushing the update parsing to the client side.
Messages on /update are now displayed on the page.
A 'refresh' update causes the page to reload.
Clarified default message.
Adding TODO to remove the /alerts path at some point.
Merge branch 'ps.rework_actions'

This branch essentially eliminates the need for the /alert handler on the
web page. There were too many custom use cases to maintain to be viable.
Instead, there is now an /update handler that will do things much more
generically. For example, it will update the message box or refresh the
page etc..