Add PlayerAbilities for diff visibility

src/main/java/net/minecraft/server/PlayerAbilities.java

@@ -0,0 +1,54 @@
+package net.minecraft.server;
+
+public class PlayerAbilities {
+
+    public boolean isInvulnerable = false;
+    public boolean isFlying = false;
+    public boolean canFly = false;
+    public boolean canInstantlyBuild = false;
+    public boolean mayBuild = true;
+    private float flySpeed = 0.05F;
+    private float walkSpeed = 0.1F;
+
+    public PlayerAbilities() {}
+
+    public void a(NBTTagCompound nbttagcompound) {
+        NBTTagCompound nbttagcompound1 = new NBTTagCompound();
+
+        nbttagcompound1.setBoolean("invulnerable", this.isInvulnerable);
+        nbttagcompound1.setBoolean("flying", this.isFlying);
+        nbttagcompound1.setBoolean("mayfly", this.canFly);
+        nbttagcompound1.setBoolean("instabuild", this.canInstantlyBuild);
+        nbttagcompound1.setBoolean("mayBuild", this.mayBuild);
+        nbttagcompound1.setFloat("flySpeed", this.flySpeed);
+        nbttagcompound1.setFloat("walkSpeed", this.walkSpeed);
+        nbttagcompound.set("abilities", nbttagcompound1);
+    }
+
+    public void b(NBTTagCompound nbttagcompound) {
+        if (nbttagcompound.hasKey("abilities")) {
+            NBTTagCompound nbttagcompound1 = nbttagcompound.getCompound("abilities");
+
+            this.isInvulnerable = nbttagcompound1.getBoolean("invulnerable");
+            this.isFlying = nbttagcompound1.getBoolean("flying");
+            this.canFly = nbttagcompound1.getBoolean("mayfly");
+            this.canInstantlyBuild = nbttagcompound1.getBoolean("instabuild");
+            if (nbttagcompound1.hasKey("flySpeed")) {
+                this.flySpeed = nbttagcompound1.getFloat("flySpeed");
+                this.walkSpeed = nbttagcompound1.getFloat("walkSpeed");
+            }
+
+            if (nbttagcompound1.hasKey("mayBuild")) {
+                this.mayBuild = nbttagcompound1.getBoolean("mayBuild");
+            }
+        }
+    }
+
+    public float a() {
+        return this.flySpeed;
+    }
+
+    public float b() {
+        return this.walkSpeed;
+    }
+}