Add integration test demonstrating that filters of queries fire events across browsers and refs
Modify last test so it fails for filter fns involving + (plus chars)
Add '+' as special character to handle for '_$queries.*' paths

Fixes issue where refs pointing to filter paths of filters using functions with
a "+" ended up not emitting up the ref chain.
Handle onRmDoc in edge case where pointerIds is undefined
Feature addition. Add ability to use dynamically changing values for filter parameters.
Fix typo
Encode ':' in filterFn hashing in a safer way
Several major fixes for filters:

- Bundle filters even when they aren't pointed to by an explicit ref.
- Add TransformBuilder#model() to get a lazily created scoped model.
- Handle bundled dynamic filter parameters in form {$ref: pathToDependencyRef}
  on fresh page load, appropriately.
- Modify mutator listener on filter dynamic parameter dependencies, so that we
  can clean the listeners up. Then, clean them up via Model 'cleanup' event.
Fixes to query unsubscribe issues.
Finish fixes to query unsubscribe. Introduce Model#alwaysSubscribe

Model#alwaysSubscribe will keep the passed in subscriptions around. The
intention here is to isolate some subscribes that should always be in scope
(e.g., a logged in user)
Require noop via racer-util/fn
Fixes to txn application and loading data from a fetch or subscribe

- Don't apply txn speculatively or post txn ack if document does not exist.
- Loading data from a fetch or subscribe should invalidate the spec model, so
  the mutation (applied via model._memory) is surfaced to the spec model via a
  spec model re-calculation
Ensure cache invalidation before another update directly to Model#_memory._data
log some context when throwing inside model.fn
Fix issue where fetch's upstream data version causes txns we are waiting acks for, are ignored, causing re-sending of txns.

Fix is to check if txnQueue is non-empty, and to only load data and callback to
app when the last txnQueue item (at that moment in time) is removed from our txnQueue
Ensure that _x is not considered a subpath of _xs
null checking
make sure code can be minified always
Add failing test - filter on sorted filter does not emit transitively
Fix for last failing test - transitive emit works on filter of sorted filter results