Metecli

Fix creating new users and drinks

Nothing fancy in this release, just:
* ignore case when searching for users during the initial setup
* refactoring
* further preparation for support of newer API versions

There are not many new features in this release. The only ones:

* the `version` subcommand
* a better fuzzy search

But there are some bugfixes:

* better support for old and new Python versions
* handle missing trailing slashes in URLs

New in this release:

* type annotations!
Metecli now uses [mypy](http://mypy-lang.org/) for type checking during development.
This shouldn't have an effect on users.
* better exception handling and output
* more output when buying stuff
* working API upgrades
* transferring money (still beta!)

New features in this release:
* reuse the connection
* support setups where the API isn't placed at `/`
* rudimentary support for different API versions

New features in this version:
* list barcodes
* add barcodes
* delete barcodes
* display config
* modify config
* log level is configurable