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/git/svn.go

@@ -1,14 +1,14 @@
 package git
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "svn",
 		Description: "Specify a username ARG",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "help", Description: "Show help for svn"},
 			{Name: "subcommand", Description: "Help about specific subcommand"},
 			{Name: "status", Description: "Show the working tree status"},
@@ -17,7 +17,7 @@ func init() {
 			{Name: "repository", Description: "The repository you want to checkout"},
 			{Name: "commit", Description: "Commit to a repository"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--password", Description: "Specify a password ARG"},
 			{Name: "--password-from-stdin", Description: "Read password from stdin"},
 			{Name: "--no-auth-cache", Description: "Do not cache authentication tokens"},