Add Java support for std::unique<T> for input parameters.

This works by transferring ownership of the underlying C++ memory
from the target language proxy class to an instance of the unique_ptr
which is passed to the wrapped function via std::move.

The proxy class has a new swigRelease() method which sets the
underlying C++ pointer for the proxy class to null, so working
in much the same way as std::unique_ptr::release(). Any attempt at
using the proxy class will be the same as if the delete() function
has been called on the proxy class. That is, using a C++ null pointer,
when a non-null pointer is usually expected.

This commit relies on the previous commit that uses std::move
on the temporary variable used for the wrapped function's input parameter
as std::unique_ptr is not copyable, it has move-only semantics.

Examples/test-suite/java_throws.i

@@ -192,6 +192,21 @@ try {
     }
   }
 %}
+%typemap(javarelease) SWIGTYPE %{
+  protected static long swigRelease($javaclassname obj) {
+    long ptr = 0;
+    if (obj != null) {
+      ptr = obj.swigCPtr;
+      obj.swigCMemOwn = false;
+      try {
+        obj.delete();
+      } catch (MyException e) {
+        throw new RuntimeException(e);
+      }
+    }
+    return ptr;
+  }
+%}
 
 %inline %{
 struct NoExceptTest {