Move classdata handling to DBICTest::Util::LeakTracer
Make the dbh error handler installer `Perl -d` friendly

GC in perl is a mess sometimes - a literal sub { ... } within a try { ... } goes
wonky, but the equivalent coderef stored in a scalar is fine >.<
Pod/comment fixes
Add a 9s soft / 9.5s hard timeout option to bin/cpan runs

This makes sure we do not abort a travis run without meaningful output