Support effect systems

[mkotsur]

• [x] split the build into modules: core, model, effects/cats-effect
• [x] implement support for cats-effect in effects/cats-effect
• [x] update tests
• [x] Implement Lambda via FLambda[Either, I, O]
• [x] fix tests
• [x] implement eff/Future
• [x] implement eff/Either
• [ ] fix todos
• [ ] draw a table of Failure kind -> Behavior
• [ ] update docs
• [ ] ask for review of cats-effect in this gitter channel
• [ ] release intermediate version
• [ ] implement support for ZIO in effects/zio
• [ ] implement support for fs2 streams in effects/fs2
• [ ] fix logging in tests
• [ ] create example projects
• [ ] fix cross-compilation?
• [ ] pick a new library name?
• [ ] update docs
• [ ] deploy artifacts to mvn central
• [ ] publish a blog post

[mkotsur]

Should input be parsed asynchronously? Possibly, yes, because you may want to do something else before accessing the input, and that can improve your lambda's performance.