Update status issue with Number widget

[dieterdemeyer]

When updating the Number widget with the 'status' payload, it doesn't seem to want to go back to a previous known status..

Example:

1. Start with initial widget and status 'normal'
2. Update status to 'warning' -> switches to warning
3. Update status to initial status 'normal' -> doesn't work
4. Update status to 'danger' -> switches to danger
   5 Update status to initial status 'status' -> doesn't work

[davefp]

There are a couple off issues here:

1. There isn't a class for the 'normal' state
2. When the status is updated, the associated CSS class is appended to the node, which doesn't override the existing class if one exists

[dieterdemeyer]

@davefp Yes, I forgot to mention I added my own status class 'normal'. I figured out that the current status wasn't being removed... Thanks for your reply...

[pushmatrix]

This will be solved when #48 is pulled in.