podman logs: fix tailing

Fix issues with tailing of container logs as described
in issue #16.  Also add in the ability to use a duration or
known time stamp formats for the --since flag.

Signed-off-by: baude <bbaude@redhat.com>

Closes: #317
Approved by: mheon

vendor/github.com/hpcloud/tail/util/util.go

@@ -1,48 +0,0 @@
-// Copyright (c) 2015 HPE Software Inc. All rights reserved.
-// Copyright (c) 2013 ActiveState Software Inc. All rights reserved.
-
-package util
-
-import (
-	"fmt"
-	"log"
-	"os"
-	"runtime/debug"
-)
-
-type Logger struct {
-	*log.Logger
-}
-
-var LOGGER = &Logger{log.New(os.Stderr, "", log.LstdFlags)}
-
-// fatal is like panic except it displays only the current goroutine's stack.
-func Fatal(format string, v ...interface{}) {
-	// https://github.com/hpcloud/log/blob/master/log.go#L45
-	LOGGER.Output(2, fmt.Sprintf("FATAL -- "+format, v...)+"\n"+string(debug.Stack()))
-	os.Exit(1)
-}
-
-// partitionString partitions the string into chunks of given size,
-// with the last chunk of variable size.
-func PartitionString(s string, chunkSize int) []string {
-	if chunkSize <= 0 {
-		panic("invalid chunkSize")
-	}
-	length := len(s)
-	chunks := 1 + length/chunkSize
-	start := 0
-	end := chunkSize
-	parts := make([]string, 0, chunks)
-	for {
-		if end > length {
-			end = length
-		}
-		parts = append(parts, s[start:end])
-		if end == length {
-			break
-		}
-		start, end = end, end+chunkSize
-	}
-	return parts
-}