Camellia block cipher support

* Tests for CBC, OFB, CFB, and ECB
* Tests will be automatically skipped if camellia support is not present
  in your OpenSSL library (e.g. OS X 10.8 with default OpenSSL)
* Test for unsupported cipher in create_block_cipher_context
* Docs for the cipher
diff --git a/docs/primitives/symmetric-encryption.rst b/docs/primitives/symmetric-encryption.rst
index 46d7c07..c4bbf0a 100644
--- a/docs/primitives/symmetric-encryption.rst
+++ b/docs/primitives/symmetric-encryption.rst
@@ -51,6 +51,15 @@
     :param bytes key: The secret key, either ``128``, ``192``, or ``256`` bits.
                       This must be kept secret.
 
+.. class:: cryptography.primitives.block.ciphers.Camellia(key)
+
+    Camellia is a block cipher approved for use by CRYPTREC and ISO/IEC.
+    It is considered to have comparable security and performance to AES, but
+    is not as widely studied or deployed.
+
+    :param bytes key: The secret key, either ``128``, ``192``, or ``256`` bits.
+                      This must be kept secret.
+
 
 Modes
 ~~~~~