Revert dig functions (#1)

* Revert "Travis shield"

This reverts commit ad26a61.

* Revert "Added some helpers for using with dig"

This reverts commit 2822665.

README.md

@@ -1,7 +1,5 @@
 # Grace pkg
 
-[![Build Status](https://travis-ci.org/chapsuk/grace.svg?branch=master)](https://travis-ci.org/chapsuk/grace)
-
 Package with single function for create base context which will be canceled on signals:
 `SIGINT`, `SIGTERM`, `SIGHUP`.
 
@@ -12,39 +10,13 @@ package main
 
 import (
     "context"
+
     "github.com/chapsuk/grace"
 )
 
 func main() {
     ctx := grace.ShutdownContext(context.Background())
-    // context can be used for long time tasks or for what else
     <-ctx.Done()
     // do graceful shutdown after context was canceled
 }
 ```
-
-## Example with dig
-
-```go
-package main
-
-import (
-    "github.com/chapsuk/grace"
-    "go.uber.org/dig"
-)
-
-func main() {
-    c := dig.New()
-
-    c.Provide(grace.NewShutdownContext)
-    c.Invoke(func(p grace.ContextParams) {
-        // nodes: {
-        //     context.Context[name="grace_context"] -> deps: [], ctor: func() grace.ContextResult
-        // }
-        // values: {
-        //     context.Context[name="grace_context"] => context.Background.WithCancel
-        // }
-        <-p.Context.Done()
-    })
-}
-```

shutdown.go

@@ -5,8 +5,6 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
-
-	"go.uber.org/dig"
 )
 
 // ShutdownContext returns child context from passed context which will be canceled
@@ -21,22 +19,3 @@ func ShutdownContext(c context.Context) context.Context {
 	}()
 	return ctx
 }
-
-// ContextResult wrap grace context for dig usage
-type ContextResult struct {
-	dig.Out
-	Context context.Context `name:"grace_context"`
-}
-
-// NewShutdownContext returns wrapped ShutdownContext func result for dig usage
-func NewShutdownContext() ContextResult {
-	return ContextResult{
-		Context: ShutdownContext(context.Background()),
-	}
-}
-
-// ContextParams contains shutdown context for dig usage
-type ContextParams struct {
-	dig.In
-	Context context.Context `name:"grace_context"`
-}