Tests use their own settings

This way example and tests are independents.

I also used memory for the sqlite3 database and added two directories to
the `.gitignore` file: `.settings`(added automatically by by eclipse) and `whoosh_index`(I don't think it's necessary to distribute spirit?)
That's ok. If someone switch from py2 to py3 should rebuild the index. Travis sets up differents envs so is not an issue either.

whosh_index directory is required, what's inside it is not and should not be added to the repo.