Changes:
- added support for standard config.h [J.J. Green]
- improved the makefile including soname and ldname links, DESTDIR, and creating missing directories on install
- fixed example program build [Jett]
- fixed kd_res_item3 and kd_res_item3f not returning the data pointer
- fixed kd_res_item3 and kd_res_item3f not checking if the position pointers are null [Mo DeJong]