Proof OID code

[pqwy]

There is a bunch of issues stemming from limitations in OID representation. OID code needs to be checked against everything mentioned in this list.

Thanks to @Andreas23.

See #2.

[pqwy]

The issues are:

• Check OID components for overflow. (ce7b457)
• The special case of OIDs 2.XXX. with XXX >= 40.
• Unlimited component size.