Feat: send full version os to the server

src/com/sheepit/client/Server.java

@@ -197,6 +197,7 @@ public class Server extends Thread {
 				.add("cpu_model_name", os.getCPU().name())
 				.add("cpu_cores", String.valueOf(user_config.getNbCores() == -1 ? os.getCPU().cores() : user_config.getNbCores()))
 				.add("os", os.name())
+				.add("os_version", os.getVersion())
 				.add("ram", String.valueOf(os.getMemory()))
 				.add("bits", os.getCPU().arch())
 				.add("version", user_config.getJarVersion())

src/com/sheepit/client/os/OS.java

@@ -29,6 +29,13 @@ public abstract class OS {
 	
 	public abstract String name();
 	
+	/** Get the full version of the os.
+	 * For example windows, should give "windows 8.1"
+	 */
+	public String getVersion() {
+		return System.getProperty("os.name").toLowerCase();
+	}
+	
 	public abstract CPU getCPU();
 	
 	public abstract long getMemory();