Add PermissionsHandler for Vault.

We'll use the VaultAPI if it's there for group checks.
This will also allow us to default to Player#hasPermission from Bukkit instead of going through each permission plugin.

Essentials/pom.xml

@@ -129,7 +129,7 @@
         <dependency>
             <groupId>net.milkbowl.vault</groupId>
             <artifactId>Vault</artifactId>
-            <version>1.2.32</version>
+            <version>1.5.4</version>
         </dependency>
         <dependency>
             <groupId>zPermissions</groupId>
@@ -139,4 +139,10 @@
             <systemPath>${project.basedir}/../lib/zPermissions.jar</systemPath>
         </dependency>
     </dependencies>
+    <repositories>
+        <repository>
+            <id>vault-repo</id>
+            <url>http://nexus.theyeticave.net/content/repositories/pub_releases</url>
+        </repository>
+    </repositories>
 </project>

Essentials/src/com/earth2me/essentials/perm/PermissionsHandler.java

@@ -97,6 +97,18 @@ public class PermissionsHandler implements IPermissionsHandler {
     public void checkPermissions() {
         final PluginManager pluginManager = ess.getServer().getPluginManager();
 
+        final Plugin vaultAPI = pluginManager.getPlugin("Vault");
+        if (vaultAPI != null && vaultAPI.isEnabled()) {
+            if (!(handler instanceof VaultHandler)) {
+                VaultHandler vault = new VaultHandler(ess);
+                if (vault.setupPermissions()) {
+                    LOGGER.log(Level.INFO, "Essentials: Using Vault based permissions.");
+                    handler = vault;
+                    return;
+                }
+            }
+        }
+
         final Plugin permExPlugin = pluginManager.getPlugin("PermissionsEx");
         if (permExPlugin != null && permExPlugin.isEnabled()) {
             if (!(handler instanceof PermissionsExHandler)) {

Essentials/src/com/earth2me/essentials/perm/VaultHandler.java

@@ -0,0 +1,51 @@
+package com.earth2me.essentials.perm;
+
+import com.earth2me.essentials.Essentials;
+import net.milkbowl.vault.permission.Permission;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.RegisteredServiceProvider;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class VaultHandler extends SuperpermsHandler {
+
+    private Essentials plugin;
+    private static Permission perms = null;
+
+    public VaultHandler(Essentials plugin) {
+        this.plugin = plugin;
+    }
+
+    public boolean setupPermissions() {
+        try {
+            Class.forName("net.milkbowl.vault.permission.Permission");
+        } catch (ClassNotFoundException e) {
+            return false;
+        }
+
+        RegisteredServiceProvider<Permission> rsp = plugin.getServer().getServicesManager().getRegistration(Permission.class);
+        perms = rsp.getProvider();
+        return perms != null;
+    }
+
+    @Override
+    public String getGroup(final Player base) {
+        return perms.getPrimaryGroup(base);
+    }
+
+    @Override
+    public List<String> getGroups(final Player base) {
+        return Arrays.asList(perms.getPlayerGroups(base));
+    }
+
+    @Override
+    public boolean inGroup(final Player base, final String group) {
+        return perms.playerInGroup(base, group);
+    }
+
+    @Override
+    public boolean hasPermission(final Player base, String node) {
+        return base.hasPermission(node);
+    }
+}