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/lerna.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:        "lerna",
 		Description: "Branch",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "*", Description: "Select all packages"},
 			{Name: "changed", Description: "Check which packages have changed since the last release"},
 			{Name: "run", Description: "Run an npm script in each package that contains that script"},
@@ -20,7 +20,7 @@ func init() {
 			{Name: "clean", Description: "Remove the node_modules directory from all packages"},
 			{Name: "create", Description: "Create a new lerna-managed package"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--npm-client", Description: "The executable to run the script with"},
 			{Name: "--concurrency", Description: "Set a max buffer length for each underlying process call"},
 			{Name: "--no-progress", Description: "Disable progress bars. This is always the case in a CI environment"},