fix(main): export as node.js module not es-module

Author: azu

package.json

@@ -13,7 +13,7 @@
   },
   "version": "1.2.1",
   "description": "textlint util convert Paragraph Node to text with SourceMap.",
-  "main": "lib/StringSource.js",
+  "main": "lib/index.js",
   "files": [
     "lib",
     "src"
@@ -32,9 +32,9 @@
     "babel-preset-es2015": "^6.1.18",
     "espower-babel": "^4.0.0",
     "markdown-to-ast": "^3.1.1",
-    "mocha": "^2.3.4",
+    "mocha": "^3.0.2",
     "power-assert": "^1.2.0",
-    "sentence-splitter": "^1.2.0"
+    "sentence-splitter": "^2.0.0"
   },
   "dependencies": {
     "object-assign": "^4.0.1",

src/index.js

@@ -0,0 +1,4 @@
+// LICENSE : MIT
+"use strict";
+import StringSource from "./StringSource";
+module.exports = StringSource;

test/StringSource-test.js

@@ -3,7 +3,7 @@
 import assert from "power-assert"
 import {parse} from "markdown-to-ast";
 import StringSource from "../src/StringSource";
-import sentenceSplitter from "sentence-splitter";
+import {split as sentenceSplitter} from "sentence-splitter";
 describe("StringSource", function () {
     describe("#toString", function () {
         it("should concat string", function () {

test/StringSource-txt-test.js

@@ -1,12 +1,11 @@
 // LICENSE : MIT
 "use strict";
 import assert from "power-assert"
-import {parse} from "markdown-to-ast";
 import StringSource from "../src/StringSource";
-import sentenceSplitter from "sentence-splitter";
-describe("StringSource", function () {
-    describe("#toString", function () {
-        it("should concat string", function () {
+import {split as sentenceSplitter} from "sentence-splitter";
+describe("StringSource", function() {
+    describe("#toString", function() {
+        it("should concat string", function() {
             const AST = {
                 "type": "Document",
                 "raw": "Str",