Begin implementation of CheckStyle style checking

By: md_5 <git@md-5.net>

paper-server/nms-patches/BlockPiston.patch

@@ -1,16 +1,12 @@
 --- a/net/minecraft/server/BlockPiston.java
 +++ b/net/minecraft/server/BlockPiston.java
-@@ -6,6 +6,18 @@
+@@ -6,6 +6,14 @@
  import java.util.List;
  import java.util.Set;
  
 +// CraftBukkit start
-+import java.util.AbstractList;
-+import java.util.Collection;
-+import java.util.Iterator;
-+import java.util.ListIterator;
-+
 +import com.google.common.collect.ImmutableList;
++import java.util.AbstractList;
 +import org.bukkit.craftbukkit.block.CraftBlock;
 +import org.bukkit.event.block.BlockPistonRetractEvent;
 +import org.bukkit.event.block.BlockPistonExtendEvent;
@@ -19,7 +15,7 @@
  public class BlockPiston extends BlockDirectional {
  
      public static final BlockStateBoolean EXTENDED = BlockProperties.g;
-@@ -112,6 +124,18 @@
+@@ -112,6 +120,18 @@
                  }
              }
  
@@ -38,7 +34,7 @@
              world.playBlockAction(blockposition, this, b0, enumdirection.a());
          }
  
-@@ -281,6 +305,48 @@
+@@ -281,6 +301,48 @@
              IBlockData[] aiblockdata = new IBlockData[j];
              EnumDirection enumdirection1 = flag ? enumdirection : enumdirection.opposite();
              Set<BlockPosition> set = Sets.newHashSet(list);