fsm

Build on private Drone CI

Reconstruct https://github.com/looplab/fsm

Why do this reconstruction?

(1) Up to 44.9% improvement of reaction speed from event to callback function.

    go test -bench=. -run=none -benchtime=1s -benchmem -cpuprofile cpu.prof -memprofile mem.prof
    2019-03-21T13:22:11.392+0800	DEBUG	System init finished.
    goos: linux
    goarch: amd64
    pkg: github.com/falconray0704/fsm/fsmBenchmark
    Benchmark_falconFSM-8    	 1000000	      1361 ns/op	     387 B/op	      12 allocs/op
    Benchmark_loopLabFSM-8   	  500000	      2473 ns/op	     531 B/op	      12 allocs/op

What optimizations in it?

(1) Using int as key in callback and transition indexing.