gr1c aut format v0 does not support initial attribute of nodes

When reading v0 files in, assign False to ->initial.  Before this
commit and after the introduction of initiality indicators, attempting
to read a gr1c aut file would leave ->initial undefined, leading to
junk values.  This could previously be demonstrated by running
examples/patching/dgridworld_2x10.edc as described in examples/README.txt
CONTRIB: readjson example updated to assert format version 1

...and use examples/counter.spc as illustration in the documentation.