@todo: manage instances in /etc/tarantool

Thanks for Anatol Pomozov

Hat tip to Alexey Panfilov

Make w3c isopub.ent entity files available locally,
since it is part of nobody-knows which package on Ubuntu,
and may be missing completely on other distributions.

On Ubuntu 13 even though it is part of mathml, it's not listed
properly in /etc/xml/catalog apparently.

This fixes xsltproc warnings and speeds up manual generation
significantly.

https://bugs.launchpad.net/tarantool/+bug/1200228
Remove the regression I introduced when trying to be to smart when
comparing integer numbers.

Numeric comparison is not memcmp compatible on x86, and I don't
know what I was smoking when I wrote a test which proved it wrong.

Apparently until I stop bullshitting ppl in the tagline I won't get
my hands on to finishing this feature (been 6 months since it was on a
branch).

Remove Debian Squeeze support.

Save tuple field offsets for indexed fields in the tuple.
Merge tuple validation and initialization of field maps in the tuple.
Make formats work for an incorrect tuple.
Make tuple_field() inline.