Updated README

README

@@ -27,6 +27,18 @@
     $ make
     $ make install
 
+4. The liblxi API
+
+    The API is small and simple. It basically includes features required for
+    discovering and communicating SCPI messages to LXI devices.
+
+    int lxi_init(void);
+    int lxi_discover_devices(lxi_devices_t **devices, int timeout, int verbose);
+    int lxi_get_device_info(lxi_devices_t *devices, lxi_device_t *device);
+    int lxi_connect(char *address);    
+    int lxi_send(int device, char *message, int length, int timeout);
+    int lxi_receive(int device, char *message, int *length, int timeout);
+    int lxi_disconnect(int device);
 
 4. API usage