Simplify updater

[dxinteractive]

Addresses #284, #285

dataparcels

• BREAKING CHANGE modifiers passed to parcel.update(), parcel.modifyUp and parcel.modifyDown now always pass entire parcel data (not just value) and expect either undefined or an object optionally containing value and meta. The meta is shallowly merged into existing meta.
• BREAKING CHANGE parcel.modifyUp() now passes changeRequest key on first param, not as second param
  • parcel.modifyUp((value, changeRequest) => {}) becomes parcel.modifyUp(({value, changeRequest}) => {})
• BREAKING CHANGE removed asRaw, as this is now the default behaviour of all updaters
• BREAKING CHANGE removed asNode, because normal updaters cover all its uses now
• BREAKING CHANGE removed parcelNode.setMeta, because parcelNode.update can now do the same thing
• BREAKING CHANGE removed parcel.spy() and parcel.spyChange()
  • use parcel.modifyDown(({value}) => { /* side effect */ }) and parcel.modifyUp(({changeRequest}) => { /* side effect */ }) instead, returning nothing
• Added createUpdater() to allow people to create and compose their own updater functions
• Fix: parcel.update() now rebases correctly, passing new data through the updater, instead of retaining the result of the first execution as it did before V2 - make update() perform an "update" and not a "setData" #285

react-dataparcels

• BREAKING CHANGE useParcelState() no longer allows value function to be used as an updater
• BREAKING CHANGE removed all deprecated components (ParcelHoc, ParcelBoundaryHoc)