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/js/asar.go

@@ -1,14 +1,14 @@
 package js
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "asar",
 		Description: "A simple extensive tar-like archive format with indexing",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "pack", Description: "Create asar archive"},
 			{Name: "directory", Description: "The directory you want to archive"},
 			{Name: "output", Description: "The name of the output file"},
@@ -18,7 +18,7 @@ func init() {
 			{Name: "filename", Description: "The name of the file you want to extract"},
 			{Name: "extract", Description: "Extract archive"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--help", Description: "Show help for asar"},
 			{Name: "--V", Description: "Output the version number"},
 		},