Replace OpenSSL with PolarSSL

Works on windows, not yet cmake.

Externals/polarssl/doxygen/input/doc_ssltls.h

@@ -0,0 +1,32 @@
+/**
+ * @file
+ * SSL/TLS communication module documentation file.
+ */
+
+/**
+ * @addtogroup ssltls_communication_module SSL/TLS communication module
+ * 
+ * The SSL/TLS communication module provides the means to create an SSL/TLS
+ * communication channel. 
+ * The basic provisions are:
+ * - initialise an SSL/TLS context (see \c ssl_init()).
+ * - perform an SSL/TLS handshake (see \c ssl_handshake()).
+ * - read/write (see \c ssl_read() and \c ssl_write()).
+ * - notify a peer that conection is being closed (see \c ssl_close_notify()).
+ *
+ *
+ * Many aspects of such a channel are set through parameters and callback
+ * functions:
+ * - the endpoint role: client or server.
+ * - the authentication mode. Should verification take place.
+ * - the Host-to-host communication channel. A TCP/IP module is provided.
+ * - the random number generator (RNG).
+ * - the ciphers to use for encryption/decryption.
+ * - session control functions.
+ * - X.509 parameters for certificate-handling and key exchange.
+ * 
+ *
+ * This module can be used to create an SSL/TLS server and client and to provide a basic
+ * framework to setup and communicate through an SSL/TLS communication channel.\n
+ * Note that you need to provide for several aspects yourself as mentioned above.
+ */