Refactor vector system to be cleaner

- Move Vector, etc. into `.math` package
- Drop many methods that will be auto-promoted anyways, eg. with
`divide(int)` and `divide(double)` the first is now gone.
- Take Block vectors into their own class hierarchy
- Make it clear throughout the API what takes blockvectors
- many more improvements

worldedit-core/src/main/java/com/sk89q/worldedit/extent/MaskingExtent.java

@@ -21,9 +21,9 @@ package com.sk89q.worldedit.extent;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
-import com.sk89q.worldedit.Vector;
 import com.sk89q.worldedit.WorldEditException;
 import com.sk89q.worldedit.function.mask.Mask;
+import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.block.BlockStateHolder;
 
 /**
@@ -65,7 +65,7 @@ public class MaskingExtent extends AbstractDelegateExtent {
     }
 
     @Override
-    public boolean setBlock(Vector location, BlockStateHolder block) throws WorldEditException {
+    public boolean setBlock(BlockVector3 location, BlockStateHolder block) throws WorldEditException {
         return mask.test(location) && super.setBlock(location, block);
     }