Several improvements from @creachadair review

- Add comments to the type-reparenting stuff.
- Factorize boilerplate into the `visitWrapper` method.
- Upgrade to Java 1.8 so the above can use lambdas.

Signed-off-by: Juanjo Alvarez <[email protected]>

Author: Juanjo Alvarez

native/pom.xml

@@ -9,8 +9,8 @@
     <version>1.0-SNAPSHOT</version>
 
     <properties>
-      <maven.compiler.source>1.6</maven.compiler.source>
-      <maven.compiler.target>1.6</maven.compiler.target>
+      <maven.compiler.source>1.8</maven.compiler.source>
+      <maven.compiler.target>1.8</maven.compiler.target>
     </properties>
 
     <distributionManagement>