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/sys/network.go

@@ -1,15 +1,15 @@
 package sys
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "curl",
 		Description: "transfer data via URL",
-		Generator:   core.FileGenerator(),
-		Options: []core.Option{
+		Generator:   spec.FileGenerator(),
+		Options: []spec.Option{
 			{Name: "-X", Description: "request method (GET/POST/PUT/DELETE)"},
 			{Name: "-H", Description: "request header"},
 			{Name: "-d", Description: "request body data"},
@@ -35,11 +35,11 @@ func init() {
 		},
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "wget",
 		Description: "non-interactive downloader",
-		Generator:   core.FileGenerator(),
-		Options: []core.Option{
+		Generator:   spec.FileGenerator(),
+		Options: []spec.Option{
 			{Name: "-O", Description: "output filename"},
 			{Name: "-q", Description: "quiet"},
 			{Name: "-v", Description: "verbose"},
@@ -56,10 +56,10 @@ func init() {
 		},
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "nc",
 		Description: "netcat - TCP/UDP tool",
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-l", Description: "listen mode"},
 			{Name: "-p", Description: "local port"},
 			{Name: "-z", Description: "port scan mode"},
@@ -70,10 +70,10 @@ func init() {
 		},
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "ping",
 		Description: "test network connectivity",
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-c", Description: "packet count"},
 			{Name: "-i", Description: "interval"},
 			{Name: "-t", Description: "TTL"},
@@ -82,10 +82,10 @@ func init() {
 		},
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "dig",
 		Description: "DNS lookup",
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "+short", Description: "short output"},
 			{Name: "+noall", Description: "no output flags"},
 			{Name: "+answer", Description: "answer section only"},
@@ -94,30 +94,30 @@ func init() {
 		},
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "nslookup",
 		Description: "query DNS",
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "ifconfig",
 		Description: "configure network interface",
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-a", Description: "all interfaces"},
 		},
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "ip",
 		Description: "show/manage network",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "addr", Description: "address management"},
 			{Name: "link", Description: "network device management"},
 			{Name: "route", Description: "routing table management"},
 			{Name: "neigh", Description: "ARP table"},
 			{Name: "rule", Description: "routing policy"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-4", Description: "IPv4 only"},
 			{Name: "-6", Description: "IPv6 only"},
 			{Name: "-br", Description: "brief output"},
@@ -125,10 +125,10 @@ func init() {
 		},
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "netstat",
 		Description: "network statistics",
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-t", Description: "TCP connections"},
 			{Name: "-u", Description: "UDP connections"},
 			{Name: "-l", Description: "listening only"},
@@ -139,10 +139,10 @@ func init() {
 		},
 	})
 
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "ss",
 		Description: "socket statistics",
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-t", Description: "TCP"},
 			{Name: "-u", Description: "UDP"},
 			{Name: "-l", Description: "listening"},