Modify the main page of the doxygen documentation to link to a new page dedicated

to Asterisk licensing information.  The licensing page includes the Asterisk license,
as well as a (not yet complete) list of 3rd party libraries that may be used, as well
as what license we receive them under.

Help filling out this list in the format that I have started in doxyref.h would be
much appreciated.  :)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@133575 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/doxyref.h

@@ -561,3 +561,46 @@ DUNDi is not itself a Voice-over IP signaling or media protocol. Instead, it pub
  * \arg See also:
  * http://www.sqlite.org
  */
+
+/*!
+ * \page Licensing Asterisk Licensing Information
+ *
+ * \section license Asterisk License
+ * \verbinclude LICENSE
+ *
+ * \section otherlicenses Licensing of 3rd Party Code
+ *
+ * This section contains a (not yet complete) list of libraries that are used
+ * by various parts of Asterisk, including related licensing information.
+ *
+ * \subsection alsa_lib ALSA Library
+ * \arg <b>Library</b>: libasound
+ * \arg <b>Website</b>: http://www.alsa-project.org
+ * \arg <b>Used by</b>: chan_alsa
+ * \arg <b>License</b>: LGPL
+ *
+ * \subsection openssl_lib OpenSSL
+ * \arg <b>Library</b>: libcrypto, libssl
+ * \arg <b>Website</b>: http://www.openssl.org
+ * \arg <b>Used by</b>: Asterisk core (TLS for manager and HTTP), res_crypto
+ * \arg <b>License</b>: Apache 2.0
+ * \arg <b>Note</b>:    An exception has been granted to allow linking of 
+ *                      OpenSSL with Asterisk.
+ *
+ * \subsection curl_lib Curl
+ * \arg <b>Library</b>: libcurl
+ * \arg <b>Website</b>: http://curl.haxx.se
+ * \arg <b>Used by</b>: func_curl, res_config_curl, res_curl
+ * \arg <b>License</b>: BSD
+ *
+ * \subsection portaudio_lib PortAudio
+ * \arg <b>Library</b>: libportaudio
+ * \arg <b>Website</b>: http://www.portaudio.com
+ * \arg <b>Used by</b>: chan_console
+ * \arg <b>License</b>: BSD
+ * \arg <b>Note</b>:    Even though PortAudio is licensed under a BSD style
+ *                      license, PortAudio will make use of some audio interface,
+ *                      depending on how it was built.  That audio interface may
+ *                      introduce additional licensing restrictions.  On Linux,
+ *                      this would most commonly be ALSA: \ref alsa_lib.
+ */