[Feature] Hide unwanted props, manage hidden props.

[danielrob]

Props coming from the actual data that are spread onto a created component can be numerous.

Unlike props added by manually the user, we
a) don't want to actually be able to delete these props such that we can't get them back
b) still want to be able to hide them.

I'm thinking an icon to the left (list mode) or above (or not at all) (list mode), that when clicked activates a prop manager tooltip / tool window that allows props to be unhidden later.

See branch spike/hideProps for a start.