4.0.1-pre.e18770b

Account for diagram zoom when dragging resizers (#16)

* add test

* add fix

* enable zoom for testing

* finish writing tests

* add fix for remaining resizers

* Revert "enable zoom for testing"

This reverts commit 69fa0aa301bedf49ddbfbb91e31c21d2f4016902.

* fix formatting

* make fields nullable

* fix nullables

* use file scoped namespaces