Add Composer support

[Composer](http://getcomposer.org) is a package manager for PHP. This allows HTML5 Shiv to be downloaded by putting "afarkas/html5shiv" into your own composer.json file.

Author: RobLoach

composer.json

@@ -0,0 +1,13 @@
+{
+  "name": "afarkas/html5shiv",
+  "description": "Defacto way to enable use of HTML5 sectioning elements in legacy Internet Explorer.",
+  "type": "component",
+  "homepage": "http://paulirish.com/2011/the-history-of-the-html5-shiv/",
+  "license": [
+    "MIT",
+    "GPL-2.0"
+  ],
+  "require": {
+    "robloach/component-installer": "*"
+  }
+}