Move cryptography.vectors to cryptography_vectors

All vectors are now stored in the subpackage in the vectors/ folder.

This package is automatically installed by setup.py test and will also
be uploaded with a matching version number by the PyPI upload task.
diff --git a/tests/test_fernet.py b/tests/test_fernet.py
index 438dc09..34760e3 100644
--- a/tests/test_fernet.py
+++ b/tests/test_fernet.py
@@ -28,15 +28,17 @@
 from cryptography.hazmat.backends import default_backend
 from cryptography.hazmat.primitives.ciphers import algorithms, modes
 
+import cryptography_vectors
+
 
 def json_parametrize(keys, filename):
-    from cryptography import vectors
-    vector_file = vectors.open_vector_file('fernet', filename)
-    data = json.load(vector_file)
-    return pytest.mark.parametrize(keys, [
-        tuple([entry[k] for k in keys])
-        for entry in data
-    ])
+    vector_file = cryptography_vectors.open_vector_file('fernet', filename)
+    with vector_file:
+        data = json.load(vector_file)
+        return pytest.mark.parametrize(keys, [
+            tuple([entry[k] for k in keys])
+            for entry in data
+        ])
 
 
 @pytest.mark.cipher
diff --git a/tests/test_utils.py b/tests/test_utils.py
index e5ab4cf..b63f1ba 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -20,6 +20,9 @@
 
 import pytest
 
+import cryptography
+import cryptography_vectors
+
 from .utils import (
     check_backend_support, check_for_iface, load_cryptrec_vectors,
     load_fips_dsa_key_pair_vectors, load_hash_vectors, load_nist_vectors,
@@ -1601,3 +1604,7 @@
     ]
 
     assert expected == load_fips_dsa_key_pair_vectors(vector_data)
+
+
+def test_vector_version():
+    assert cryptography.__version__ == cryptography_vectors.__version__
diff --git a/tests/utils.py b/tests/utils.py
index 226d64f..3e35970 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -15,9 +15,11 @@
 
 import collections
 
+import pytest
+
 import six
 
-import pytest
+import cryptography_vectors
 
 
 HashVector = collections.namedtuple("HashVector", ["message", "digest"])
@@ -66,9 +68,8 @@
 
 
 def load_vectors_from_file(filename, loader):
-    from cryptography import vectors
-    vector_file = vectors.open_vector_file('hazmat', 'primitives', filename)
-    return loader(vector_file)
+    with cryptography_vectors.open_vector_file(filename) as vector_file:
+        return loader(vector_file)
 
 
 def load_nist_vectors(vector_data):