Added soundex (sigh)

Doc/lib/lib.tex

@@ -93,6 +93,7 @@ to Python and how to embed it in other applications.
 \input{libregex}
 \input{libregsub}
 \input{libstruct}
+\input{libsoundex}
 
 \input{libmisc}			% Miscellaneous Services
 \input{libmath}

Doc/lib/libsoundex.tex

@@ -0,0 +1,25 @@
+\section{Standard Module \sectcode{soundex}}
+\stmodindex{soundex}
+
+\renewcommand{\indexsubitem}{(in module soundex)}
+The soundex algorithm takes an English word, and returns an
+easily-computed hash of it; this hash is intended to be the same for
+words that sound alike.  This module provides an interface to the
+soundex algorithm.
+
+Note that the soundex algorithm is quite simple-minded, and isn't
+perfect by any measure.  Its main purpose is to help looking up names
+in databases, when the name may be misspelled -- soundex hashes common
+misspellings together.
+
+\begin{funcdesc}{get_soundex}{string}
+Return the soundex hash value for a word; it will always be a
+6-character string.  \var{string} must contain the word to be hashed,
+with no leading whitespace; the case of the word is ignored.
+\end{funcdesc}
+
+\begin{funcdesc}{sound_similar}{string1, string2}
+Compare the word in \var{string1} with the word in \var{string2}; this
+is equivalent to 
+\code{get_soundex(\var{string1})==get_soundex(\var{string2})}.
+\end{funcdesc}