Manual: Update usrsctp_init() documentation

The documentation for usrsctp_init() is not up to date anymore. It
mentions the UDP-Encapsulation port as the only parameter. By now there
are three parameters.

Commit b724b61 ("Add support for registering a printf() callback for
debug output. This is required by Firefox.") was the last to extend the
API. It seems a simulatenous update to the documentation had been
forgotten.

Introduce the new API to the documentation.

Signed-off-by: Philipp Stanner <[email protected]>

Manual.md

@@ -96,7 +96,10 @@ All system calls start with the prefix `usrsctp_` to distinguish them from the k
 Every application has to start with `usrsctp_init()`. This function calls `sctp_init()` and reserves the memory necessary to administer the data transfer. The function prototype is
 
 ```c
-void usrsctp_init(uint16_t udp_port)
+void usrsctp_init(uint16_t udp_port,
+                  int (*conn_output)(void *addr, void *buffer,
+                                     size_t length, uint8_t tos, uint8_t set_df),
+                  void (*debug_printf)(const char *format, ...))
 ```
 
 As it is not always possible to send data directly over SCTP because not all NAT boxes can process SCTP packets, the data can be sent over UDP. To encapsulate SCTP into UDP a UDP port has to be specified, to which the datagrams can be sent. This local UDP port  is set with the parameter `udp_port`. The default value is 9899, the standard UDP encapsulation port. If UDP encapsulation is not necessary, the UDP port has to be set to 0.

Manual.tex

@@ -171,7 +171,10 @@ \subsubsection{usrsctp\_init()}
 The function prototype is 
 \begin{verbatim}
 void
-usrsctp_init(uint16_t udp_port)
+usrsctp_init(uint16_t udp_port,
+             int (*conn_output)(void *addr, void *buffer,
+                                size_t length, uint8_t tos, uint8_t set_df),
+	     void (*debug_printf)(const char *format, ...))
 \end{verbatim}
 As it is not always possible to send data directly over SCTP because not all NAT boxes can
 process SCTP packets, the data can be sent over UDP. To encapsulate SCTP into UDP