* Get everything working with GHC 8
* Fix all warnings (on GHC 8)
* Improve code style consistency
* Make benchmarks run in a separate process, and include GC time
* Remove the inherent memory leak (retained results) in the benchmarks
* Use -Wall for all build outputs
* Use -auto-all for profiling
* Create Data.WeakBag (a better way of managing subscribers)
* Update Data.Functor.Misc to use new primitives exposed by Data.Dependent.Map
* Add Show, GShow, and ShowTag instances for Const2
* Add Functor (Dynamic t)
* Make Dynamic a primitive supplied by Reflex implementations
* Add Incremental, a new primitive reactive datatype
* Add mergeIncremental, a merge that can have inputs added and removed efficiently
* Make all time-invariant operations on Dynamics pure
* Add a phantom type to Spider, to distinguish different Spider domains
* Add a mutex around Spider domains
* Add a way of creating new Spider domains
* Substantially refactor Spider internals to increase clarity
* Add a (much) more useful error message when an Event causality loop is detected; with profiling enabeled, it will include the stack traces of all Events participating in the loop
* Clean up tests and benchmarks
