Start an AUTHORS file.
Add a .gitignore file.
Update Makefile, but maybe I want autognu.

I want build time control of what programs to enable and disable and
what libraries to link with.  Maybe a configure script is better.
Begin conversion of the Makefiles to automake and autoconf.
Remove INIT_MAIN preprocessor usage in src/utmp.c

This sort of construct is frustrating to deal with when editing source.
I prefer just creating separate files for the differences.  So I did
that.

    utmp.c - Original file reduced to non-INIT_MAIN versions of
             write_wtmp() and write_utmp().
    initutmp.c - utmp.c with the INIT_MAIN versions of
                 write_wtmp() and write_utmp().
    writeutmp.c - New file with write_utmp_wtmp() function.
Patch src/ tree so it builds correctly under automake and autoconf.

This is just a bunch of assorted patches to deal with the source tree
restructuring.  More meaningful changes coming later.
Update top level README file.