Remove i/I keybindings

Removing the currently unused keybindings for [Shift]I used
for cycling of HUD types. Also remove this from the help
dialog.

May be re-added for the next release, but currently there is
no HUD-type cycling implemented.

Nasal/gui.nas

@@ -1223,7 +1223,7 @@ var common_aircraft_keys = {
         { name: "g/G",       desc: "gear up/down" },
         { name: "h",         desc: "cycle HUD (head up display)" },
         { name: "H",         desc: "cycle HUD brightness" },
-        { name: "i/Shift-i", desc: "normal/alternative HUD" },
+       #{ name: "i/Shift-i", desc: "normal/alternative HUD" },
        #{ name: "j",         desc: "decrease spoilers" },
        #{ name: "k",         desc: "increase spoilers" },
         { name: "l",         desc: "toggle tail-wheel lock" },

keyboard.xml

@@ -669,6 +669,7 @@ top down before the key bindings are parsed.
   </binding>
  </key>
 
+ <!-- no longer used 
  <key n="73">
   <name>I</name>
   <desc>Switch to and toggle alternative HUD types</desc>
@@ -676,7 +677,7 @@ top down before the key bindings are parsed.
    <command>nasal</command>
    <script>aircraft.HUD.cycle_type()</script>
   </binding>
- </key>
+ </key> -->
 
  <key n="77">
   <name>M</name>
@@ -891,6 +892,7 @@ top down before the key bindings are parsed.
   </binding>
  </key>
 
+ <!-- no longer used 
  <key n="105">
   <name>i</name>
   <desc>Normal HUD</desc>
@@ -899,6 +901,7 @@ top down before the key bindings are parsed.
    <script>aircraft.HUD.normal_type()</script>
   </binding>
  </key>
+ -->
 
  <key n="106">
   <name>j</name>