Fix typing errors.

Author: jaywcjlove

src/components/CodeMirror/index.tsx

@@ -1,4 +1,4 @@
-import CodeMirror from 'codemirror';
+import * as CodeMirror from 'codemirror';
 import 'codemirror/mode/markdown/markdown';
 import React, { Component } from 'react';
 import { DomEvent, IDefineModeOptions, IEventDict, IGetSelectionOptions, IInstance, ISetScrollOptions, ISetSelectionOptions } from '../../common/codemirror';

src/components/PreviewMarkdown/index.tsx

@@ -1,6 +1,6 @@
 import classnames from 'classnames'
 import hljs from 'highlight.js';
-import React from 'react';
+import * as React from 'react';
 import ReactMarkdown, { MarkdownAbstractSyntaxTree } from 'react-markdown';
 import { IProps } from '../../common/props';
 import './hljs.less';