An unnecesary file (props.h) was removed due to linking problems against the
installed shared library; linking now works fine. Special properties stuff was
completely rewritten. Three new functions and a cfg_property_type enumeration were
added, ugly macros were removed, and a working example was added to the distribution.
Installation and documentation building stuff was improved, and documentation was
updated.

   version 0.5.1, Juny 11, 2002 (official release)
   
     * unnecesary file props.h removed due to linking problems
       against installed shared library; linking now works fine
     * (special) properties stuff completely rewritten; three new
       functions and cfg_property_type enumeration added, ugly
       macros removed
     * working example added to distribution
     * installation and documentation building stuff improvements
     * documentation update