Overview
 About the Hexadecimal conversion routines:
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 The Expand Library has a special section dedicated to the conversion
 of Hexadecimal types. These functions are found here.  All routines
 presented here are written in Assembly. Thus compact and quite fast,
 which can be important when implementing some Hex-Dump.

 The XPhex2Bin() function is the only one who converts a hexadecimal
 character string to a binary character string. If you want to convert
 to numbers, you must then use bin2i() or the other applicable
 equivalent functions.

 XPbin2Hex() and XPhexStr() do nearly the same, with the difference that
 XPhexStr() inserts spaces between the Hex characters. XPbin2Hex() just
 makes plain Hex-Codes.

 XPhexStrip() is a function to strip High (above 128) and Low (below 32)
 characters from strings. useful for Hex-Dumps, but not really a Hex
 function, although it would mostly be used in combination with Hex type
 functions, that's why I named it XPhexStrip(). XPhexLStrip() was added for
 convenience, it strips only Low characters, as the High characters are
 generally accepted by most printers currently. Both functions are written
 in Assembly, which makes them compact but also quite more efficient that
 when one's got to write it in Clipper code.