chore(move): cleanup unused stuff

Related to bpmn-io/bpmn-js#105
chore(util/Text): remove default padding

We removed the default padding from the text rendering utility. This
ensures we have no unwanted side-effects.

BREAKING CHANGE:

- Removed default padding. To restore the behavior, override
the property during initialization:

new TextUtil({ padding: 5 })

or during label creation

textUtil.createText( ..., { padding: 5 })
fix(css): real hide elements

Use display:none instead of visibility:hidden to make elements
disappear.
chore(navigation): reduce notable move threshold