Display individual transfer progress

Improve progress printing by displaying individual file progress, as well
as a moving average speed with ETA. Example output:

2015/09/15 16:38:21
Transferred:    183599104 Bytes (4646.49 kByte/s)
Errors:                 0
Checks:                 1
Transferred:            0
Elapsed time:       38.5s
Transferring:
 * 01_06_14.mp3: 33% done. avg: 1280.5, cur: 1288.8 kByte/s. ETA: 1m12s
 * 01_12_15.mp3: 33% done. avg: 1002.2, cur:  943.4 kByte/s. ETA: 1m17s
 * 01_13_14.mp3: 48% done. avg: 1456.8, cur: 1425.2 kByte/s. ETA: 39s
 * 01_19_15.mp3: 28% done. avg: 1226.9, cur: 1114.4 kByte/s. ETA: 1m37s

fs/operations.go

@@ -196,7 +196,7 @@ tryAgain:
 			ErrorLog(src, "Failed to open: %s", err)
 			return
 		}
-		in := NewAccount(in0) // account the transfer
+		in := NewAccount(in0, src) // account the transfer
 
 		if doUpdate {
 			actionTaken = "Copied (updated existing)"
@@ -621,7 +621,7 @@ func syncFprintf(w io.Writer, format string, a ...interface{}) (n int, err error
 	return fmt.Fprintf(w, format, a...)
 }
 
-// List the Fs to stdout
+// List the Fs to the supplied writer
 //
 // Shows size and path
 //
@@ -632,7 +632,7 @@ func List(f Fs, w io.Writer) error {
 	})
 }
 
-// List the Fs to stdout
+// List the Fs to the supplied writer
 //
 // Shows size, mod time and path
 //
@@ -646,7 +646,7 @@ func ListLong(f Fs, w io.Writer) error {
 	})
 }
 
-// List the Fs to stdout
+// List the Fs to the supplied writer
 //
 // Produces the same output as the md5sum command
 //
@@ -664,7 +664,7 @@ func Md5sum(f Fs, w io.Writer) error {
 	})
 }
 
-// List the directories/buckets/containers in the Fs to stdout
+// List the directories/buckets/containers in the Fs to the supplied writer
 func ListDir(f Fs, w io.Writer) error {
 	for dir := range f.ListDir() {
 		syncFprintf(w, "%12d %13s %9d %s\n", dir.Bytes, dir.When.Format("2006-01-02 15:04:05"), dir.Count, dir.Name)