[ Implemented ] Labled Element and Constraint with custom name

[Opity69]

Motivation / Existing Problem
unable to tell which Ratio constraint belongs to which line etc

Description
allow for naming points and constraints with custom names( such and Core Box ratio constraint)

Alternative Solutions
N/A

Mockup

[hlorus]

This is partly planned for the next milestone, see: #56. I'd say it's a higher priority for entities as they overlap more often.

Also note that elements get highlighted whenever the tooltip pops up.