Added services manager framework. Services are interfaces that specifies capabilities to be implemented by providers. Example services include economy, <insert example 2>, etc.

src/main/java/org/bukkit/plugin/RegisteredServiceProvider.java

@@ -0,0 +1,50 @@
+package org.bukkit.plugin;
+
+/**
+ * A registered service provider.
+ * 
+ * @author sk89q
+ * @param <T> Service
+ */
+public class RegisteredServiceProvider<T>
+        implements Comparable<RegisteredServiceProvider<?>> {
+
+    private Class<T> service;
+    private Plugin plugin;
+    private T provider;
+    private ServicePriority priority;
+    
+    public RegisteredServiceProvider(Class<T> service, T provider,
+            ServicePriority priority, Plugin plugin) {
+
+        this.service = service;
+        this.plugin = plugin;
+        this.provider = provider;
+        this.priority = priority;
+    }
+    
+    public Class<T> getService() {
+        return service;
+    }
+
+    public Plugin getPlugin() {
+        return plugin;
+    }
+
+    public T getProvider() {
+        return provider;
+    }
+
+    public ServicePriority getPriority() {
+        return priority;
+    }
+
+    public int compareTo(RegisteredServiceProvider<?> other) {
+        if (priority.ordinal() == other.getPriority().ordinal()) {
+            return 0;
+        } else {
+            return priority.ordinal() < other.getPriority().ordinal() ? 1 : -1;
+        }
+    }
+    
+}