test case for event refs with context
index refactor that attempts to fix issues and simplify reasoning

moves index propagation out of rebind
ref resolver creation searches up-tree for indices
resolvers register with their target fragments to receive updates
makes object key interation first-class instead of overriding the index
resoltions carry a type indicator to avoid turning number-like keys into
  numbers
object iterations can access both the key and ordinal index
index refs in components no longer get added to the viewmodel
iterations can now switch between array and object
make sure isolated components are isolated from outside indices and special refs
extend isolated component index ref tests
add test for object section updates #1476
fix breaking changes in index refactor
reverse mapping on computation
allow empty string partials
support empty string return as no-op for most plugins"
basic transfer of mapping and depencies between viewmodels
prevent ownership transfer of computation. refactoring
merge
merge the latest and greatest
avoid partial expression inception invovling recursive data structures
Merge pull request #1501 from evs-chris/dev

Avoid partial expression inception invovling recursive data structures
working on reversing reversed mapping
merge changes
Merge pull request #1488 from ractivejs/empty-things

Support for no-op plugins when empty strings
let mapping transfer existing dependents
allow inflight event unsubscribe, fixes #1504