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/fs/chmod.go

@@ -1,16 +1,16 @@
 package fs
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "chmod",
 		Description: "change file permissions",
 		MaxArgs:     2, // 1 option + 1 file
-		Subcommands: []core.Subcommand{},
-		Options: []core.Option{
+		Subcommands: []spec.Subcommand{},
+		Options: []spec.Option{
 			{Name: "-R", Description: "apply recursively to directories"},
 			{Name: "--recursive", Description: "apply recursively to directories"},
 			{Name: "-v", Description: "verbose: show each file processed"},
@@ -31,8 +31,8 @@ func init() {
 
 // modeGenerator suggests common chmod mode strings as the first argument,
 // then falls back to file suggestions for subsequent arguments
-func modeGenerator() core.GeneratorFunc {
-	filegen := core.FileGenerator(".sh", ".py", ".bin", ".run")
+func modeGenerator() spec.GeneratorFunc {
+	filegen := spec.FileGenerator(".sh", ".py", ".bin", ".run")
 
 	commonModes := []struct {
 		mode string
@@ -63,7 +63,7 @@ func modeGenerator() core.GeneratorFunc {
 		{"664", "rw-rw-r-- (group can read+write)"},
 	}
 
-	return func(tokens []string, prefix string, partial string) []core.Suggestion {
+	return func(tokens []string, prefix string, partial string) []spec.Suggestion {
 		argCount := 0
 		for i := 1; i < len(tokens); i++ {
 			t := tokens[i]
@@ -73,10 +73,10 @@ func modeGenerator() core.GeneratorFunc {
 		}
 
 		if argCount == 0 {
-			var results []core.Suggestion
+			var results []spec.Suggestion
 			for _, m := range commonModes {
-				if partial == "" || core.HasPrefixCI(m.mode, partial) {
-					results = append(results, core.Suggestion{
+				if partial == "" || spec.HasPrefixCI(m.mode, partial) {
+					results = append(results, spec.Suggestion{
 						Cmd:  m.mode,
 						Desc: m.desc,
 					})