Use phetioIDs of elements instead of phetioID of links to those elements.

[KatieWoe]

For phetsims/qa#1335

In the PhET-iO Examples doc, these elements are given, but they are defined elsewhere. It may be better use those other elements instead.

vectorAddition.equationsScreen.view.sceneNodes.cartesianSceneNode.equationAccordionBox.equationNodes.additionEquationNode.aCoefficientPicker.valueProperty might be better as vectorAddition.equationsScreen.model.scenes.cartesianScene.vectorSet.allVectors.aVector.coefficientProperty

vectorAddition.equationsScreen.view.sceneNodes.cartesianSceneNode.equationAccordionBox.equationNodes.additionEquationNode.bCoefficientPicker.valueProperty might be better as vectorAddition.equationsScreen.model.scenes.cartesianScene.vectorSet.allVectors.bVector.coefficientProperty

[matthew-blackman]

Good catch! I also updated equationsScreen to vectorAdditionEquationsScreen - see #434.

Close if OK.

[pixelzoom]

Please do not close. We are in RC testing, so assign to me for patching in 1.2 branches.

[KatieWoe]

Things look ok