refactor(commands): separate commands and its core into two folders (#32)

- I think it would be better if one for commands only, one for the spec
handling core logic so people won't be confused by the core logic inside
the commands folder (cleaner I guess)
- Regen docs

commands/sys/asr.go

@@ -1,14 +1,14 @@
 package sys
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "asr",
 		Description: "Can be a disk image, /dev entry, or volume mountpoint",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "help", Description: "Displays asr usage information"},
 			{Name: "version", Description: "Displays asr version"},
 			{Name: "restore", Description: "Restores a disk image or volume to another volume"},
@@ -17,7 +17,7 @@ func init() {
 			{Name: "interface", Description: "The network interface to be used for multicasting"},
 			{Name: "configuration", Description: "Configuration file in standard property list format"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--source", Description: "Can be a disk image, /dev entry, or volume mountpoint"},
 			{Name: "--target", Description: "Can be a /dev entry, or volume mountpoint"},
 			{Name: "--file", Description: "When performing a multicast restore, --file can be specified instead of --target"},