Implement Helm < 1.0.0 functionality as 3rd party libraries

[z0w0]

With Helm 1.0.0, I got rid of a bit of the old functionality that didn't mesh with the subscription/command style. It'd be cool to see the following old core features be re-implemented as third party libraries:

• FRP.Helm.Random: RNG that interacts with subscriptions/commands. It might be cool to have a subscription that triggers event randomly (although obviously it would need some use).
• FRP.Helm.Automaton: it'd be cool to see something like the old automaton that works nicely with subs/commands.

[z0w0]

After further thought:

• Cmd.execute is perfectly capable of running any of the random package's functions in the context of Helm
• Automaton is unnecessary in the current version of Helm