v0.2.0

Folds v0.2.0

Diff since v0.1.0

Merged pull requests:

• Use Run.jl (#5) (@tkf)
• Install JuliaFolds/*.jl from GitHub (#6) (@tkf)
• Update: Transducers (#11) (@tkf)
• Add collect(_, ::Scheduler) (#13) (@tkf)
• Implement reducers using executors (#19) (@tkf)