Guard variable declarations to unbreak non-namespaced builds.

ok tb@

Hide global _it symbols in asn1t.h

ok tb@

Make ASN1_{primitive,template}_* internal

These were long removed from the public OpenSSL API, so we can do the
same. Remove ASN1_template_{d2i,i2d}() - those are unused internally.

ok jsing

Unbreak the namespace build after a broken mk.conf and tool misfire had
me aliasing symbols not in the headers I was procesing.

This unbreaks the namespace build so it will pass again

ok tb@

Hide symbols in asn1 and bio

ok jsing@