Improve README, add Wiki as submodule

Ensures developers get a full offline copy of documentation when cloning repo.

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "docs/wiki"]
+	path = docs/wiki
+	url = https://github.com/WagicProject/wagic.wiki

README.md

@@ -1,5 +1,4 @@
-#Wagic the Homebrew
-
+# Wagic the Homebrew
 
 [![Build Status](https://travis-ci.org/WagicProject/wagic.png?branch=master)](https://travis-ci.com/WagicProject/wagic)
 [![Build status](https://ci.appveyor.com/api/projects/status/7j4fbr6m62aqej59/branch/master)](https://ci.appveyor.com/project/xawotihs/wagic/branch/master)
@@ -7,22 +6,37 @@
 
 ## Description
 
-Wagic, the Homebrew, is a C++ game engine that allows to play card games against an AI on
+**Wagic, the Homebrew** is a C++ game engine that allows to play card games against an AI on:
 - Android (phones and tablets) 
 - iOS (iPhone/iPad)
 - Sony PSP
 - Windows desktops 
 - MacOS
-- Linux and derivated like Maemo or Meego 
+- Linux and derivatives like Maemo or Meego 
 
-It is highly customizable and allows the player to tweak the rules / create their own cards, their own themes, etc... 
+It is highly customizable and allows the player to tweak the rules, create their own cards, their own themes, etc... 
 
+#### [Download from GitHub Releases!](https://github.com/WagicProject/wagic/releases)
+
+![Screenshot of shop from wololo.net](docs/img/shop.jpg)
+
+
+### Documentation
 
 Info, downloads, discussions and more at http://wololo.net/forum/index.php
 
-![alt text](http://wololo.net/wagic/wp-content/uploads/2009/10/shop.jpg "Screenshot")
-
+Developer information from [the Wagic Wiki](https://github.com/WagicProject/wagic/wiki) is also included in the [wagic/docs/](docs) folder.
 
 
 ### Sample round play-through video
-[![IMAGE ALT TEXT HERE](http://img.youtube.com/vi/WUFSAPZuDIk/0.jpg)](http://www.youtube.com/watch?v=WUFSAPZuDIk)
+
+[![Wagic, The Homebrew sample playthrough](docs/img/Wagic%2C%20The%20Homebrew%20sample%20playthrough.jpg)](http://www.youtube.com/watch?v=WUFSAPZuDIk)
+*Wagic, The Homebrew sample playthrough on YouTube by Rolz73, 6 Feb 2014*
+
+
+## Sister projects
+
+- [WagicSyntaxPlugin
+](https://github.com/Vitty85/WagicSyntaxPlugin) by Vitty85 for [Notepad++](https://notepad-plus-plus.org/downloads/)
+- [Forge](https://www.slightlymagic.net/forum/viewforum.php?f=26), a Java-based game engine similar to Wagic ([Source](https://git.cardforge.org/core-developers/forge))
+- [XMage](https://github.com/magefree/mage), a Java-based online multiplayer digital CCG