feat(views): adds (de)hydration of views and template vars.

Dehydrated views are views that are structurally fixed, but their
directive instances and viewports are purged.

Support for local bindings is added to the view.
fix(Change Detection): fix merge error
style(Change Detection): rename WatchGroupDispatcher to ChangeDispatcher
style: misc minor changes
perf(Change Detection): Track the range & group on changes only

1.4x speed improvement with Firefox

There is no need to track the range & group for all the records but only
for the records that have changed.
perf(Change Detection): remove the usage of getters/setters

- Firefox is 2.4x faster (90 vs 221ms)
- Chrome is 24% slower (15.5 vs 12.5ms)

Chrome is still 5.8x faster than Firefox
perf(Change Detection): inline isPresent() & isBlank()

- isPresent() -> !== null
- isBlank() -> === null

- 20% faster in Chrome
- Firefox is about the same speed.