add license badge to readme

README.md

@@ -2,13 +2,16 @@
 
 Copyright © 2008–2019, Christopher Alan Mosher, Shelton, Connecticut, USA, <[email protected]>.
 
+[![License](https://img.shields.io/github/license/cmosher01/Apple-II-Source.svg)](https://www.gnu.org/licenses/gpl.html)
 [![Latest Release](https://img.shields.io/github/release-pre/cmosher01/Apple-II-Source.svg)](https://github.com/cmosher01/Apple-II-Source/releases/latest)
 [![Build Status](https://travis-ci.com/cmosher01/Apple-II-Source.svg?branch=master)](https://travis-ci.com/cmosher01/Apple-II-Source)
 [![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-v1.4%20adopted-ff69b4.svg)](./code-of-conduct.md)
 [![Donate](https://img.shields.io/badge/Donate-PayPal-green.svg)](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=CVSSQ2BWDCKQ2)
 
 Home page: <https://mosher.mine.nu/apple2>
 
+---
+
 This package contains reverse-engineered source code for
-the **System Software** and **Disk Operating System Software (DOS)**
+the **System Software (ROMs)** and **Disk Operating System Software (DOS)**
 of the `Apple ][` series computers from Apple, Inc.