Initial commit: up to and including data exchange functionality

This initial commit for the PyDTLS package includes the following functionality:

    * DTLS cookie exchange, using secure hmac cookies
    * A platform-independent routing UDP demultiplexer
    * SSL handshaking over UDP using the DTLS protocol
    * Datagram exchange using the DTLS protocol
    * SSL shutdown over UDP

The package is structured as follows:

    * dtls:               top-level package
    * dtls.demux:         demultiplexer package; automatically loads a
                          demultiplexer appropriate for the currently executing
                          platform
    * dtls.demux.router:  a routing demux for platforms whose network stacks
                          cannot assign incoming UDP packets to sockets based
                          on the sockets' connection information
    * dtls.demux.osnet:   a demux that uses the operating system's UDP packet
                          routing functionality
    * dtls.err:           package-wide error handling and error definitions
    * dtls.sslconnection: a client and server-side connection class for
                          UDP network connections secured with the DTLS protocol
    * dtls.openssl:       a ctypes-based wrapper for the OpenSSL library
    * dtls.test:          test scripts, utilities, and unit tests

The following binaries are provided:

    * libeay32.dll: cryptographic portion of the OpenSSL library
    * ssleay32.dll: protocol portion of the OpenSSL library (depends on former)
    * cygcrypto-1.0.0.dll: as libeay32.dll, but with debugging symbols
    * cygssl-1.0.0.dll: as ssleay32.dll, but with debugging symbols

All binaries have been built with the MinGW tool chain, targeted for msvcr90.
The unstripped dll's can be debugged on Windows with gdb. Cygwin is not used.

dtls/test/certs/ca-cert.pem

@@ -0,0 +1,13 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

dtls/test/certs/server-cert.pem

@@ -0,0 +1,36 @@
+Certificate:
+    Data:
+        Version: 1 (0x0)
+        Serial Number: 1 (0x1)
+        Signature Algorithm: md5WithRSAEncryption
+        Issuer: C=US, ST=Washington, O=Ray CA Inc, CN=RayCAInc
+        Validity
+            Not Before: Sep 21 21:16:18 2012 GMT
+            Not After : Sep 21 21:16:18 2013 GMT
+        Subject: C=US, ST=Washington, O=Ray Srv Inc, CN=RaySrvInc
+        Subject Public Key Info:
+            Public Key Algorithm: rsaEncryption
+                Public-Key: (512 bit)
+                Modulus:
+                    00:b8:f7:77:26:6c:9d:25:f5:e1:ca:28:b4:6a:0b:
+                    15:81:13:0e:51:c3:b2:ba:57:5b:69:ff:cb:bb:86:
+                    d9:f9:4d:33:1f:43:92:a1:89:2f:d0:08:5b:cf:b7:
+                    a1:2b:ea:06:31:e5:32:fd:2b:86:54:09:fb:24:bc:
+                    a3:ce:56:22:f1
+                Exponent: 65537 (0x10001)
+    Signature Algorithm: md5WithRSAEncryption
+        12:4c:55:17:c1:c4:19:5f:0d:e2:66:00:84:37:22:62:9b:6d:
+        9e:76:fd:a5:82:f5:a2:41:c6:ae:16:88:16:ab:bd:0f:5d:0b:
+        7c:fd:52:2a:9b:3f:ea:cf:ea:35:29:37:61:a2:15:8f:27:56:
+        38:71:1f:eb:1a:f8:cc:99:22:17
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

dtls/test/certs/server-key.pem

@@ -0,0 +1,10 @@
+-----BEGIN PRIVATE KEY-----
+MIIBVAIBADANBgkqhkiG9w0BAQEFAASCAT4wggE6AgEAAkEAuPd3JmydJfXhyii0
+agsVgRMOUcOyuldbaf/Lu4bZ+U0zH0OSoYkv0Ahbz7ehK+oGMeUy/SuGVAn7JLyj
+zlYi8QIDAQABAkAygtnV82lC2Y/Mbis+nkJEGlkZuRCQ1JRRMRqI3n2eF6CviqF3
+PiBXIEEExzKihC9bvbHKTAkYDLr+/4YpbiQBAiEA7JLS5Lp7KI/ayWwEzl2r5XXu
+k/cbH++A4zZz6A9XIsECIQDIJ8ciDa5/VGyQnYMzBNgKnwaFDDBOiEUFDaU/9ZN8
+MQIgCG3Gw819G9ncQrbtiOi/eiJ0iKMSPVYMMow7HvaE9UECIQCLyQwPwlJd5s4z
+aW4ZkYZ4VHuvK8YI8q6RSuhf9Nhd4QIgFbRNdEeehgrzGzGug2yVCMzVzS3MQNBJ
+6LqBZaPlFsM=
+-----END PRIVATE KEY-----