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/golang/goreleaser.go

@@ -1,14 +1,14 @@
 package golang
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "goreleaser",
 		Description: "Deliver Go binaries as fast and easily as possible",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "b", Description: "Builds the current project"},
 			{Name: "c", Description: "Checks if configuration is valid"},
 			{Name: "completion", Description: "Generate the autocompletion script for the specified shell"},
@@ -22,7 +22,7 @@ func init() {
 			{Name: "r", Description: "Releases the current project"},
 			{Name: "help", Description: "Help about any command"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--clean", Description: "Remove the dist folder before building"},
 			{Name: "--config", Description: "Load configuration from file"},
 			{Name: "--deprecated", Description: "Force print the deprecation message - tests only"},