Extract providers to their own package

This is just doing that and making it compile :)

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

provider/file.go

@@ -1,84 +0,0 @@
-package provider
-
-import (
-	"os"
-	"path/filepath"
-	"strings"
-
-	"github.com/BurntSushi/toml"
-	"github.com/containous/traefik/log"
-	"github.com/containous/traefik/safe"
-	"github.com/containous/traefik/types"
-	"gopkg.in/fsnotify.v1"
-)
-
-var _ Provider = (*File)(nil)
-
-// File holds configurations of the File provider.
-type File struct {
-	BaseProvider `mapstructure:",squash"`
-}
-
-// Provide allows the provider to provide configurations to traefik
-// using the given configuration channel.
-func (provider *File) Provide(configurationChan chan<- types.ConfigMessage, pool *safe.Pool, constraints types.Constraints) error {
-	watcher, err := fsnotify.NewWatcher()
-	if err != nil {
-		log.Error("Error creating file watcher", err)
-		return err
-	}
-
-	file, err := os.Open(provider.Filename)
-	if err != nil {
-		log.Error("Error opening file", err)
-		return err
-	}
-	defer file.Close()
-
-	if provider.Watch {
-		// Process events
-		pool.Go(func(stop chan bool) {
-			defer watcher.Close()
-			for {
-				select {
-				case <-stop:
-					return
-				case event := <-watcher.Events:
-					if strings.Contains(event.Name, file.Name()) {
-						log.Debug("File event:", event)
-						configuration := provider.loadFileConfig(file.Name())
-						if configuration != nil {
-							configurationChan <- types.ConfigMessage{
-								ProviderName:  "file",
-								Configuration: configuration,
-							}
-						}
-					}
-				case error := <-watcher.Errors:
-					log.Error("Watcher event error", error)
-				}
-			}
-		})
-		err = watcher.Add(filepath.Dir(file.Name()))
-		if err != nil {
-			log.Error("Error adding file watcher", err)
-			return err
-		}
-	}
-
-	configuration := provider.loadFileConfig(file.Name())
-	configurationChan <- types.ConfigMessage{
-		ProviderName:  "file",
-		Configuration: configuration,
-	}
-	return nil
-}
-
-func (provider *File) loadFileConfig(filename string) *types.Configuration {
-	configuration := new(types.Configuration)
-	if _, err := toml.DecodeFile(filename, configuration); err != nil {
-		log.Error("Error reading file:", err)
-		return nil
-	}
-	return configuration
-}