pcb_disassemble options -[bho?], enable roundtrips

[rurban]

Attached patch changes the pcb_disassemble output to enable roundtrips, to print proper pasm on -b.

./pbc_disassemble -?
pbc_disassemble - dump or convert parrot bytecode (PBC) files
usage:
pbc_disassemble [-bh] [--bare|--header-only] [file.pbc]
pbc_disassemble -o converted.pasm file.pbc

  -b             ... bare .pasm without header and left column
  -h             ... dump Constant-table header only
  -o filename    ... output to filename

$ parrot -o i.pbc -a - <<EOF
print 0x10203040
end
EOF
$ ./pbc_disassemble -b i.pbc
=head1 Constant-table

PMC_CONST(0): 'ParrotInterpreter'
PMC_CONST(1): i.pasm
PMC_CONST(2):
PMC_CONST(3): (null)

=cut

# Current Source Filename 'i.pasm'
        print_ic 270544960
        end

In detail: =head1 Constant-table ... and =cut

embed.h needs a new enum Parrot_disassemble_options, because Parrot_disassemble() sits in embed.c

Reading from stdin is supported.

-o filename is ignored for now.

[rurban]

patch went in with 0.9.1, r36671