Remove: ping and synchronous actions

[dxinteractive]

These were introduced to give dataparcels a way of calling back data from children so that derived data from each child's modifyChange function could be analyzed from the parent and acted upon. This is not a good pattern, as it tries to reverse the direction of who is in control of what. Parcel should know statically about what is beneath them, but never have to trigger actions on them.

[dxinteractive]

https://github.com/blueflag/dataparcels/releases/tag/v0.18.0