added readme file.

Pulled information from http://sparkle.andymatuschak.org/

README.markdown

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+# Sparkle 
+is an easy-to-use software update framework for Cocoa developers.
+
+* True self-updating--no work required from the user.
+
+* Displays release notes to the user via WebKit.
+
+* Displays a detailed progress window to the user.
+
+* Supports authentication for installing in secure locations.
+
+* Really, really easy to install.
+
+* Uses appcasts for release information.
+
+* The user can choose to automatically download and install all updates.
+
+* Seamless integration—there's no mention of Sparkle; your icons and app name are used.
+
+* Supports DSA signatures for ultra-secure updates.
+
+* Sparkle requires no code in your app, so it's trivial to upgrade or remove the module.
+
+## New in Sparkle 1.5:
+
+* Optionally sends user demographic information to the server when checking for updates.
+
+* Dual-mode garbage collection support for any memory management style.
+
+* Sparkle doesn't bug the user until second launch for better first impressions.
+
+* Sparkle can install .pkg files for more complicated products.
+
+* Supports bundles, preference panes, plugins, and other non-.app software.
+
+* Supports branches due to minimum OS version requirements.
+
+* Deep delegate support to make Sparkle work exactly as you need.
+
+* Tons of other stuff! [Read more about what's new.](http://andymatuschak.org/articles/2008/05/31/sparkle-15b1-now-available/ "Sparkle 1.5b1: now available!")