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/rush.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:        "rush",
 		Description: "Projects",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "add", Description: "Adds one or more dependencies to the package.json and runs rush update"},
 			{Name: "init", Description: "Initializes a new repository to be managed by Rush"},
 			{Name: "init-autoinstaller", Description: "Initializes a new autoinstaller"},
@@ -21,7 +21,7 @@ func init() {
 			{Name: "rebuild", Description: "Clean and rebuild the entire set of projects"},
 			{Name: "tab-complete", Description: "Provides tab completion"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-t", Description: "Multi-Project Build Tool"},
 			{Name: "-p", Description: "Specify package to the dependencies of the current project"},
 			{Name: "--exact", Description: "If specified, the dependency will be added to all projects"},