Standardize examples/docs on Schema::Loader schema naming

A new user is very likely to encounter this naming convention these days
This comment is woefully outdated

Setting DBIC_TRACE=1 won't help either - we use the fast-path insert which
mean the user won't see anything
Teach the example scripts how to find their DB from anywhere
Update example Result classes for proper DDL generation

Also given that this is one of the first things a newbie sees, it is prudent
to stick to canonical definition
Generalize the SQLite DDL generation tool (see next commit)
Automatically regenerate the example ddl/db from the example Schema
Sync Example.pod with reality, though in fairness it just needs to die...
Adjust DBD::Firebird travis init
I did manage to screw up locking in parallel testing after all

We try to grab a new engine lock within the same test before releasing
the one for the previous engine
Switch travis-perl tests to 5.18
Try a different CPAN mirror - something odd is going on with develooper
Temporary work around yet another cpanm issue