directory structure change to work with glide

glide has its own requirements. My previous workaround caused me some
code checkin errors. Need to fix this.

weed/command/command.go

@@ -0,0 +1,71 @@
+package command
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+)
+
+var Commands = []*Command{
+	cmdBenchmark,
+	cmdBackup,
+	cmdCompact,
+	cmdFix,
+	cmdServer,
+	cmdMaster,
+	cmdFiler,
+	cmdUpload,
+	cmdDownload,
+	cmdShell,
+	cmdVersion,
+	cmdVolume,
+	cmdExport,
+	cmdMount,
+}
+
+type Command struct {
+	// Run runs the command.
+	// The args are the arguments after the command name.
+	Run func(cmd *Command, args []string) bool
+
+	// UsageLine is the one-line usage message.
+	// The first word in the line is taken to be the command name.
+	UsageLine string
+
+	// Short is the short description shown in the 'go help' output.
+	Short string
+
+	// Long is the long message shown in the 'go help <this-command>' output.
+	Long string
+
+	// Flag is a set of flags specific to this command.
+	Flag flag.FlagSet
+
+	IsDebug *bool
+}
+
+// Name returns the command's name: the first word in the usage line.
+func (c *Command) Name() string {
+	name := c.UsageLine
+	i := strings.Index(name, " ")
+	if i >= 0 {
+		name = name[:i]
+	}
+	return name
+}
+
+func (c *Command) Usage() {
+	fmt.Fprintf(os.Stderr, "Example: weed %s\n", c.UsageLine)
+	fmt.Fprintf(os.Stderr, "Default Usage:\n")
+	c.Flag.PrintDefaults()
+	fmt.Fprintf(os.Stderr, "Description:\n")
+	fmt.Fprintf(os.Stderr, "  %s\n", strings.TrimSpace(c.Long))
+	os.Exit(2)
+}
+
+// Runnable reports whether the command can be run; otherwise
+// it is a documentation pseudo-command such as importpath.
+func (c *Command) Runnable() bool {
+	return c.Run != nil
+}