added session saving and loading functions

docs/manual.rst

@@ -18,6 +18,7 @@ the ``session``, it contains the main loop that serves all torrents.
 The basic usage is as follows:
 
 * construct a session
+* load session state from settings file (see `load_state() save_state()`_)
 * start extensions (see `add_extension()`_).
 * start DHT, LSD, UPnP, NAT-PMP etc (see `start_dht() stop_dht() set_dht_settings() dht_state() is_dht_running()`_
   `start_lsd() stop_lsd()`_, `start_upnp() stop_upnp()`_ and `start_natpmp() stop_natpmp()`_)
@@ -30,6 +31,7 @@ The basic usage is as follows:
 
 * save resume data for all torrent_handles (optional, see
   `save_resume_data()`_)
+* save session state (see `load_state() save_state()`_)
 * destruct session object
 
 Each class and function is described in this manual.
@@ -115,6 +117,9 @@ The ``session`` class has the following synopsis::
 				| add_default_plugins
 			, int alert_mask = alert::error_notification);
 
+		void load_state(lazy_entry const& e);
+		void save_state(entry& e) const;
+
 		torrent_handle add_torrent(
 			add_torrent_params const& params);
 		torrent_handle add_torrent(
@@ -270,6 +275,22 @@ returns. So, it's advised that any kind of interface (such as windows) are close
 destructing the session object. Because it can take a few second for it to finish. The
 timeout can be set with ``set_settings()``.
 
+load_state() save_state()
+-------------------------
+
+	::
+
+		void load_state(lazy_entry const& e);
+		void save_state(entry& e) const;
+
+loads and saves all session settings, including dht_settings, encryption settings and proxy
+settings. ``save_state`` writes all keys to the ``entry`` that's passed in, which needs to
+either not be initialized, or initialized as a dictionary.
+
+``load_state`` expects a ``lazy_entry`` which can be built from a bencoded buffer with
+``lazy_bdecode``.
+
+
 pause() resume() is_paused()
 ----------------------------