Set up space profiling.
Correct space semantics for `stepper`.

Any value that is stored in the graph over more than a single atomic evaluation must be stored in WHNF. This implies that latch values must be forced to WHNF before storing them. On the other hand, only latch values can be stored for a longer time, so they are the only place where we need to do this.

The model semantics have been corrected in a similar way.
Introduce a two-phase approach for pulse/latch evaluation and remove the knot for latch evaluation.

This will make it easier to get the strictness of latches correct.
Type checks.
Finish up implementation of two-phase approach.

Two recursion tests fail. The switchB test fails only intermittedly, probably some issues with observable sharing.
Add test for leak reported in issue #25
Use the new `Data.Vault.Strict` to store the latch values in a `Vault` that is strict both in the spine and the values.

Fix strictness of `applyL` to force applications of `readValueL` that would otherwise retain the `Vault` of old latch values.

Fix issue #52.
Kill 'reactive-banana-ji' for good.
Commit last changes, though they are broken. Going to be rewritten anyway.
Refactor implementation to separate concerns. Introduce 'newPulse' to replace the former 'fromAddHandler'.
Move modules 'Internal0' stuff to a new module prefix 'Prim'.
Major change to the implementation of 'Latch', to support recursion better.
Add cache functionality to the 'Build' monad.
Change type of 'compile' to build on existing 'Network'.
Minor additions to public API in Reactive.Banana.Prim
Fix observable sharing for 'newPulse' by introducing a 'Key a' argument. Rename it to 'newInput'.
Add dynamic event switching primitives to 'Reactive.Banana.Prim' API.
Rework output handling.

Remove 'tagFuture' combinator and tie-the-knot evaluation.
Remove 'grOutput' from graph type.
Add new node type 'Output' as a possible child for a pulse in the evaluation order.
Add 'addHandlerLatch' function that can sample updated latch values.
Update infrastructure for memory profiling.

Confirm that there is no space leak when using 'accumL'.
Update API for 'Prim.Dependencies'.
Proper implementation of 'Prim.Order' so that we finally have a push-driven implementation that can handle dynamic event switching.