add note about kybd shortcut to open debug popup window

README.md

@@ -84,7 +84,7 @@ The attributes listed below are used in *config.json* to configure **Spoor**, an
 
 >>**_scormVersion** (string): This property defines what version of SCORM is targeted. Only SCORM 1.2 is officially supported by Adapt. SCORM 2004 should work, but the Adapt team don't include this version in testing. To enable SCORM 2004 support, change this value to `"2004"` and include the relevant SCORM 2004 packaging files (*imsmanifest.xml* and others - you can find examples over at [scorm.com](http://scorm.com/scorm-explained/technical-scorm/content-packaging/xml-schema-definition-files/)). The default is `"1.2"`.  
 
->>**_showDebugWindow** (boolean): If set to `true`, a pop-up window will be shown on course launch that gives detailed information about what SCORM calls are being made. This can be very useful for debugging SCORM issues. Note that this pop-up window will appear automatically if the SCORM code encounters an error, even if this is set to `false`. The default is `false`.  
+>>**_showDebugWindow** (boolean): If set to `true`, a pop-up window will be shown on course launch that gives detailed information about what SCORM calls are being made. This can be very useful for debugging SCORM issues. Note that this pop-up window will appear automatically if the SCORM code encounters an error, even if this is set to `false`. You can also hold down the keys 'd', 'e' and 'v' to force the popup window to open. The default is `false`. 
 
 >>**_suppressErrors** (boolean): If set to `true`, an alert dialog will NOT be shown when a SCORM error occurs. Errors will still be logged but the user will not be informed that a problem has occurred. Note that setting **_showDebugWindow** to `true` will still cause the debug popup window to be shown on course launch, this setting merely suppresses the alert dialog that would normally be shown when a SCORM error occurs. *This setting should be used with extreme caution as, if enabled, users will not be told about any LMS connectivity issues or other SCORM tracking problems.*