POPT as an ASN.1 parser in POPT-2.0

Both POPT and ASN.1 are TLV (type/length/value) table driven
parsers even if the usage cases are quite different (options & args != RPC
marshalling).

Mostly what I would attempt is to map either the libtasn1 format (its
a tree of named nodes in an array) or the NSS ASN.1 format (which
is directives not unlike POPT_ARGFLAG_FOO but without named nodes)
into a popt table.

Then I'd stub in a method to substitute an ASN.1 blob for parsing
rather that argv[arc] as POPT currently uses.

I'd likely duplicate the methods used while parsing argv[argc] into
a different code path before attempting to unify (gulp) ARGV and ASN.1
parsing within the same routines.

The ulterior motive for attempting ASN.1 parsing would be to look carefully
at vectorizing POPt with callbacks. If I can trick POPT into parsing
ASN.1 I'm almost positive that POPT parsing will be quite a bit more
general than currently.