Add shrink_to_fit to deque

Cython/Includes/libcpp/deque.pxd

@@ -81,3 +81,6 @@ cdef extern from "<deque>" namespace "std" nogil:
         void resize(size_t, T&)
         size_t size()
         void swap(deque&)
+
+        # C++11 methods
+        void shrink_to_fit()

tests/run/cpp_stl_cpp11.pyx

@@ -10,6 +10,7 @@ from libcpp.queue cimport priority_queue
 from libcpp.vector cimport vector
 from libcpp.pair cimport pair
 from libcpp.map cimport map
+from libcpp.deque cimport deque
 
 
 def test_vector_functionality():
@@ -44,6 +45,18 @@ def test_queue_functionality():
     return "pass"
 
 
+def test_deque_functionality():
+    """
+    >>> test_deque_functionality()
+    'pass'
+    """
+    cdef:
+        deque[int] int_deque = deque[int]()
+    int_deque.push_back(77)
+    int_deque.shrink_to_fit()
+    return "pass"
+
+
 def test_priority_queue_functionality():
     """
     >>> test_priority_queue_functionality()