[Bleeding] Add ProjectileSource interface. Addresses BUKKIT-1038, BUKKIT-1156

src/main/java/org/bukkit/projectiles/BlockProjectileSource.java

@@ -0,0 +1,13 @@
+package org.bukkit.projectiles;
+
+import org.bukkit.block.Block;
+
+public interface BlockProjectileSource extends ProjectileSource {
+
+    /**
+     * Gets the block this projectile source belongs to.
+     *
+     * @return Block for the projectile source
+     */
+    public Block getBlock();
+}