Update documentation

README

@@ -11,22 +11,27 @@ TODO: System clock frequency should be a multiple of
   1.8432MHz for perfect USART. This means we would need
   an external crystal oscillator.
 
-TODO: Do we need to handle backspaces for interactive
-serial consoles?! Overkill?!
-
 ### Supported Commands
 
-Optional decimal point for numbers.
-
-- START
-- RESET
+  - RUN
   - STOP
-- SET TEMP 20.0
-- SET DEWP 60.0
+  - TEMP <float>
+  - DEWP <float>
+
+  Decimal point for numbers is optional. Make sure you
+  have disabled hardware flow control on the client side.
+
+  TODO: Do we need to handle backspaces for interactive
+  serial consoles?! Overkill?!
 
 ### Web Interface Example
 
   There is a little example web interface you can check
-out in the opt/webgui directory. This simple php page
+  out in the opt/webgui directory. The simple php page
   demonstrates how you can create a custom interface for
   your drybox. For more info see the README file there.
+
+  You may need to run the following command to load the
+  optional submodules if you can't see the webgui folder:
+
+    git submodule update --init