bump liboctave, libinterp, and libgui version numbers for release * libgui/Makefile.am, libinterp/Makefile.am: Increment current and age version numbers and set revision version number to 0 as recommended by the libtool manual when interfaces have been added. * liboctave/Makefile.am: Increment as recommended by the libtool manual when the library sources change but no interfaces have changed.