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/python/conda.go

@@ -1,14 +1,14 @@
 package python
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "conda",
 		Description: "Name of environment",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "activate", Description: "Activate an environment"},
 			{Name: "deactivate", Description: "Deactivate an environment"},
 			{Name: "clean", Description: "Remove unused packages and caches"},
@@ -32,7 +32,7 @@ func init() {
 			{Name: "upgrade", Description: "Alias for conda update"},
 			{Name: "files", Description: "Package files to convert"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "-n", Description: "Name of environment"},
 			{Name: "-p", Description: "Full path to environment location (i.e. prefix)"},
 			{Name: "--dev", Description: "Use locally built packages. Identical to '-c local'"},