Add support for comma-separated titles in prospect command

Example usage:

    clearbit prospect -title CEO,COO company.com

Closes #17

Author: siadat

cmd/clearbit/prospect.go

@@ -3,6 +3,7 @@ package main
 import (
 	"github.com/codegangsta/cli"
 	"github.com/thoughtbot/clearbit"
+	"strings"
 )
 
 var prospectCommand = cli.Command{
@@ -27,9 +28,14 @@ func prospect(ctx *cli.Context) error {
 		name      = ctx.String("name")
 		role      = ctx.String("role")
 		seniority = ctx.String("seniority")
-		titles    = ctx.StringSlice("title")
+		titlesCSV = ctx.StringSlice("title")
 	)
 
+	titles := make([]string, 0)
+	for _, title := range titlesCSV {
+		titles = append(titles, strings.Split(title, ",")...)
+	}
+
 	if domain == "" {
 		return requiredArgError("Usage: clearbit prospect <domain>")
 	}