README updates.

- Fix link to client repo (it's DMDirc/DMDirc not DMDirc/client)
- Add shiny screenshot
- Add information on actually installing and running

README.md

 DMDirc is an IRC client written in Java. It's cross-platform, hugely
 configurable, and is easily extensible with a robust plugins system.
 
+![DMDirc Screenshot](etcd/screenshot.png?raw=true)
+
+Getting DMDirc
+--------------------------------------------------------------------------------
+
+To download and run the latest stable version of DMDirc, download an installer
+or archive for your platform from
+[the releases page](https://github.com/DMDirc/DMDirc/releases).
+
+If there's not a distribution for your platform, you can download the Jar file
+instead. You will need to manually install OpenJDK 8 or newer in this case.
+
+Repositories
+--------------------------------------------------------------------------------
+
 This repository doesn't actually contain the source for DMDirc. Instead it's
 split over four different components, each with their own repository:
 
-* [client](https://github.com/DMDirc/client):
+* [client](https://github.com/DMDirc/DMDirc):
   contains the main guts of the client
 * [parser](https://github.com/DMDirc/parser):
   an interface for parsers and a full IRC parser
 above is included as a submodule, and there are some handy top-level build
 scripts for bundling everything together.
 
-Getting Started
+Development
 --------------------------------------------------------------------------------
 
 ### Prerequisites
 to run all of the tests in the project and compile and run an actual client to
 make sure everything actually still works!
 
-You can see an overview of open pull requests across all of the DMDirc projects [here](https://github.com/pulls?q=is%3Aopen+is%3Apr+user%3Admdirc).
+You can see an overview of open pull requests across all of the DMDirc projects
+[here](https://github.com/pulls?q=is%3Aopen+is%3Apr+user%3Admdirc).
 
 ### Continuous Integration and Code Coverage