adds ArrayValue.to_numpy()

Author: Christopher Doris

docs/src/juliacall-reference.md

@@ -132,6 +132,7 @@ copy of the original array.
 - `shape`: Tuple of lengths in each dimension.
 - `copy()`: A copy of the array.
 - `reshape(shape)`: A reshaped view of the array.
+- `to_numpy()`: Convert to a numpy array.
 `````
 
 `````@customdoc

src/jlwrap/array.jl

@@ -330,6 +330,9 @@ function init_jlwrap_array()
             except ImportError:
                 pass
             return arr
+        def to_numpy(self, dtype=None):
+            import numpy
+            return numpy.array(self, dtype=dtype)
     """, @__FILE__(), "exec"), jl.__dict__)
     pycopy!(pyjlarraytype, jl.ArrayValue)
 end