Fix a typo and move a word

Refer to RFC 3779, 2.1.2 for encoding of ranges

Mention sections 2.1.1 and 2.1.2 in STANDARDS

Point out that the result of IPAddressRange_new() is an invalid range
since it should be a prefix.

fix one copy and paste error: d2i_*() decode rather than encode;
plus some minor markup and punctuation fixes

Document X509v3_{addr,asid}_subset.3

First RFC 3779 page without a BUG section. It could have one, but I'm
in a lenient mood right now. Maybe it's just that this is bad but not
quite as bad as EVP.

Various small tweaks in the RFC 3779 docs

Mention a few more bugs and unify manpage descriptions

Document X509v3_{addr,asid}_inherits(3)

Also note another bug in X509v3_asid_{canonize,is_canonical}(3).

Document X509v3_addr_get_{afi,range}(3)

Document the guts of RFC 3779 IPAddrBlocks

Let's just say there's room for improvement...