Add a Doxyfile and preliminary module-level docs.

src/http.h

@@ -1,5 +1,16 @@
 #pragma once
 
+/**
+** \defgroup http HTTP Server
+** This is a HTTP server.
+**
+** It can listen on multiple ports.  It supports IPv4
+** and IPv6.  It handles websocket connections.  Requests can be handled
+** immediately or at a later time.  It is very bare bones, and that is a
+** feature.
+** @{
+*/
+
 #include <stdbool.h>
 #include <stddef.h>
 
@@ -35,7 +46,13 @@ typedef struct _tf_http_request_t
 typedef void(tf_http_callback_t)(tf_http_request_t* request);
 typedef void(tf_http_cleanup_t)(void* user_data);
 
+/**
+** Create an HTTP server using the given libuv loop.
+** @param loop A libuv loop to use.
+** @return An HTTP server instance.
+*/
 tf_http_t* tf_http_create(uv_loop_t* loop);
+
 void tf_http_set_trace(tf_http_t* http, tf_trace_t* trace);
 int tf_http_listen(tf_http_t* http, int port, tf_tls_context_t* tls, tf_http_cleanup_t* cleanup, void* user_data);
 void tf_http_add_handler(tf_http_t* http, const char* pattern, tf_http_callback_t* callback, tf_http_cleanup_t* cleanup, void* user_data);
@@ -53,3 +70,5 @@ void tf_http_request_send(tf_http_request_t* request, const void* data, size_t s
 void tf_http_request_websocket_upgrade(tf_http_request_t* request);
 
 const char* tf_http_status_text(int status);
+
+/** @} */