1.0.0-alpha.1

CHANGES:

This is an initial prerelease. This version includes the following
operators:

• McCarthy's amb.
• Scheme's call/cc (aka. Reynolds' escape).
• Filinski's monadic reflection for any monad.
• Kiselyov's interface for programming with typed multi-prompt continuations.
• Danvy and Filinski's shift and reset (and some of their variations).
• Felleisen's control and prompt.
• Felleisen'c C operator.