New tooltip in config tab

_locales/en/messages.json

@@ -1373,5 +1373,8 @@
     },
     "configHelp1": {
         "message": "RSSI is a measurement of signal strength and is very handy so you know when your aircraft is going out of range or if it is suffering RF interference."
+    },
+    "configHelp2": {
+        "message": "Arbitrary board rotation in degrees, to allow mounting it sideways / upside down / rotated etc. When running external sensors, use the sensor alignments (Gyro, Acc, Mag) to define sensor position independent from board orientation. "
     }
 }

tabs/configuration.html

@@ -104,6 +104,9 @@
             <div class="gui_box grey">
                 <div class="gui_box_titlebar">
                     <div class="spacer_box_title" i18n="configurationBoardAlignment"></div>
+                    <div class="helpicon cf_tip">
+                        <div class="cf_tooltiptext" i18n="configHelp2" style="display:none;"></div>
+                    </div>
                 </div>
                 <div class="spacer_box">
                     <div style="width:60%; float:left;">