Strassen::GPX: -name support also for Twig variant

... including tests for -as => "route", -name => ...
Strassen::GPX: global directive "title" sets route name
Strassen::GPX: -meta vs -name/-number

Make sure that <name> and <number> are created only once in presence
of a given or calculated -meta object.

This used to fail for tracks where <name> was automatically created
from start and goal point names, and <name> was additionally taken
from the title global directive. The generated xml file was invalid
according to the gpx schema.
Pod documentation for Strassen::GPX
data update (minor)