Adds deprecated functions for old Sender (#246)

@anuraaga was right as there is a link error otherwise, noticed in
cassandra.

```
java.lang.NoSuchMethodError: zipkin2.reporter.brave.AsyncZipkinSpanHandler.create(Lzipkin2/reporter/Sender;)Lzipkin2/reporter/brave/AsyncZipkinSpanHandler;
	at brave.cassandra.Tracing.<init>(Tracing.java:75)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
```

Signed-off-by: Adrian Cole <adrian@tetrate.io>

brave/src/main/java/zipkin2/reporter/brave/AsyncZipkinSpanHandler.java

@@ -46,12 +46,22 @@
  * @since 2.14
  */
 public final class AsyncZipkinSpanHandler extends SpanHandler implements Closeable, Flushable {
-  /** @since 2.14 */
+  /** @deprecated Since 3.2, use {@link #create(BytesMessageSender)} */
+  @Deprecated public static AsyncZipkinSpanHandler create(Sender sender) {
+    return create((BytesMessageSender) sender);
+  }
+
+  /** @since 3.2 */
   public static AsyncZipkinSpanHandler create(BytesMessageSender sender) {
     return newBuilder(sender).build();
   }
 
-  /** @since 2.14 */
+  /** @deprecated Since 3.2, use {@link #newBuilder(BytesMessageSender)} */
+  @Deprecated public static Builder newBuilder(Sender sender) {
+    return newBuilder((BytesMessageSender) sender);
+  }
+
+  /** @since 3.2 */
   public static Builder newBuilder(BytesMessageSender sender) {
     if (sender == null) throw new NullPointerException("sender == null");
     return new Builder(sender);

core/src/main/java/zipkin2/reporter/AsyncReporter.java

@@ -36,18 +36,29 @@
  */
 // This is effectively, but not explicitly final as it was not final in version 2.x.
 public class AsyncReporter<S> extends Component implements Reporter<S>, Closeable, Flushable {
+  /** @deprecated Since 3.2, use {@link #create(BytesMessageSender)} */
+  @Deprecated public static AsyncReporter<zipkin2.Span> create(Sender sender) {
+    return create((BytesMessageSender) sender);
+  }
 
   /**
    * Builds a json reporter for <a href="https://zipkin.io/zipkin-api/#/">Zipkin V2</a>. If http,
    * the endpoint of the sender is usually "http://zipkinhost:9411/api/v2/spans".
    *
    * <p>After a certain threshold, spans are drained and {@link BytesMessageSender#send(List) sent}
    * to Zipkin collectors.
+   *
+   * @since 3.2
    */
   public static AsyncReporter<zipkin2.Span> create(BytesMessageSender sender) {
     return new Builder(sender).build();
   }
 
+  /** @deprecated Since 3.2, use {@link #builder(BytesMessageSender)} */
+  @Deprecated public static Builder builder(Sender sender) {
+    return builder((BytesMessageSender) sender);
+  }
+
   /** Like {@link #create(BytesMessageSender)}, except you can configure settings such as the timeout. */
   public static Builder builder(BytesMessageSender sender) {
     return new Builder(sender);