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/ops/cf.go

@@ -1,14 +1,14 @@
 package ops
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "cf",
 		Description: "Cloudfoundry cli",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "app", Description: "Display health and status for app"},
 			{Name: "APP_NAME", Description: "The app you want to get health and status for"},
 			{Name: "ssh", Description: "Display health and status for app"},
@@ -60,7 +60,7 @@ func init() {
 			{Name: "unbind-route-service", Description: "Unbind a service instance from an HTTP route"},
 			{Name: "create-user-provided-service", Description: "Make a user-provided service instance available to CF apps"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--guid", Description: "Display health and status for app"},
 			{Name: "-v", Description: "Verbose output"},
 			{Name: "-a", Description: "API endpoint (e.g. https://api.example.com)"},