Overview
 About the Norton Guide Reading routines:
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 The Expand library now sports a quite special feature: It provides
 the Clipper programmer with the means to read Norton Guide Databases.
 This feature offers the possibility to greatly enhance Clipper
 Applications in regard to Static Data. Now, Norton Guides need
 not be only guides, but can be used to Create an extensive Help
 System, or some other source of information for your Applications.

 One Norton Guide can be opened at one time, Opening such guide
 does not require much memory. The only amount of memory required
 is some information concerning the Norton Guide, and the Entry
 currently loaded (generally around 5-6Kb). When calling the Functions
 used to load data, the information is read from the Norton Guide.

 I cannot give a Guarantee that the routines would work on every guide,
 I have found out the lay-out of Norton Guides by trial and error, and
 have found that every Norton Guide encountered to this day is
 formatted as expected. However, to my knowledge, the lay-out is not
 officially documented. However, I'm quite confident that these routines
 should work on every possible Norton Guide that you may encounter or
 make yourself. Just like the Norton Guide alike programs popping-up
 these days. The routines also recognize Norton Guides generated by the
 EH compiler from SofSolutions.

 Note that NGopen() is to be called before any of the other NGxxx()
 can be called. Also close the Guide with NGclose() when you're done.
 The only exception to that are NGlook() and NGdir(), which return
 Norton Guide information possibly required before opening the Guide,
 they can be called whenever you want.

 Using these routines might seem difficult at first, but I'm confident
 that once having experimented a bit, all will become quite clear. Also
 have a look at the Demo programs supplied, they quite clearly point out
 typical usage of most of the functions. Currently all possible attributes
 in the Norton Guide are ignored and not returned by the different functions,
 this because it would be too much work to convert them to screen attributes.
 All text returned is therefore plain text, without codes.

 Note that these routines would of course ideally be part of a Norton Guide
 Class, just like TBrowse or Get. Once we get a good and documented way of
 creating those classes, I will put these routines as part of a Class. So
 expect some changes in the future here.

 Note also that the functions in this section all start with NG instead of
 XP used mostly in this library. This is chosen to discriminate them from
 the other functions, and make it possible for me, for instance, to make
 a downstripped library containing only these routines. The source code to
 these routines is available when ordering the "Complete" Library, and not
 included in the "Enhanced" version, as customizing would generally not be
 necessary.