Integrate LZMA compression of source embedded in .hex files

microbit/overrideupload/app.manifest

@@ -20,6 +20,7 @@ CACHE:
 ./jquery-2.1.4.min.js
 ./font-awesome.min.css
 ./external/FileSaver.min.css
+./external/lzma_worker-min.js
 https://az742082.vo.msecnd.net/files/images/bg-site-header.png
 https://az742082.vo.msecnd.net/files/images/bg-site-header-mobile.png
 https://az742082.vo.msecnd.net/files/icons/micro-bit_primary_colour_196x196.png

microbit/overrideupload/index.html

@@ -631,6 +631,7 @@ statusMsg("js initialized");
 </style>
 <script type="text/javascript"> statusMsg("css imported"); </script>
 <script src="./external/FileSaver.min.js" type="text/javascript"></script>
+<script src="./external/lzma_worker-min.js" type="text/javascript"></script>
 <script src="./browser.js" type="text/javascript"></script>
 <script type="text/javascript">
 statusMsg("browser detector loaded");

www/external/ossinfo.md

@@ -4,8 +4,18 @@
 
 * id: 27248
 * project: https://github.com/eligrey/FileSaver.js
-* commit: https://github.com/eligrey/FileSaver.js/commit/54c04285aedaec973f5f725f18c624a3fb12cf63
+* commit: https://github.com/eligrey/FileSaver.js/commits/54c04285aedaec973f5f725f18c624a3fb12cf63
 
 ### files:
 
 * FileSaver.min.js
+
+## LZMA JS
+
+* id: 27102
+* project: https://github.com/nmrugg/LZMA-JS
+* commit: https://github.com/nmrugg/LZMA-JS/commits/45da2a27e4c826393fb95b6348150dbf43f1e312 
+
+### files:
+
+* lzma_worker-min.js