Refactoring, added LocalsHelper class to make it easier (hopefully) for

the reader to follow local variable accesses within the code generator.

I've renamed some variable names to be consistent with DemoProxyResult.
e.g. wOffset was used in implementProcess and getUnsafe but
usage in DemoProxyResult calls that rOffset.

jctools-experimental/src/main/java/org/jctools/channels/proxy/LocalsHelper.java

@@ -0,0 +1,48 @@
+package org.jctools.channels.proxy;
+
+import static java.lang.System.out;
+
+import org.objectweb.asm.Type;
+
+public final class LocalsHelper {
+    private int nextLocalIndex = 0;
+
+    private LocalsHelper() {
+    };
+
+    public int newLocal(Class<?> cls) {
+        Type type = Type.getType(cls);
+        return newLocal(type);
+    }
+
+
+    private int newLocal(Type type) {
+        final int myIndex = nextLocalIndex;
+        nextLocalIndex += type.getSize();
+        return myIndex;
+    }
+
+    public static LocalsHelper forStaticMethod() {
+        return new LocalsHelper();
+    }
+
+    public static LocalsHelper forInstanceMethod() {
+        LocalsHelper helper = new LocalsHelper();
+        helper.newLocal(Object.class);
+        return helper;
+    }
+
+    public static void main(String[] args) throws Exception {
+        LocalsHelper helper =
+                LocalsHelper.forInstanceMethod();
+        out.println(helper.newLocal(int.class));
+        out.println(helper.newLocal(int.class));
+        out.println(helper.newLocal(long.class));
+        out.println(helper.newLocal(double.class));
+        out.println(helper.newLocal(boolean.class));
+        out.println(helper.newLocal(Object.class));
+        out.println(helper.newLocal(Object.class));
+        out.println(helper.newLocal(Object.class));
+        out.println();
+    }
+}