refactor configuration parsing

* use a single default configuration, share/isso.conf
* try to use config.new in some tests which are decoupled

A few tests now depend on `isso.dist` to show that they (or the used
objects) have too much dependencies and need to be rewritten.
add esperanto translation
Preparing release 0.9.2
Back to development: 0.9.3
Merge branch 'legacy/0.9'