Support for positional commands

[lsrdg]

Right now the script is called as: $ python tatoeba-karini.py -d links.
The use of optional flags may be working here, but it is extremely
counter-intuitive. It is okay if you are already inside the project's
repository and have quick access to the file.

As of v0.0.1, it would make sense to pack the software and make it avaialable
at least on pypi and/or aur.
Having a prepackaged software is great but automatically imposes a distance
from the source files. In this situation, it would make sense if the user
(despite of its current working directory) could do something like: $ tatoeba-karini download links.
More verbose, but easier to deal with.

If possible, I would like to include a short form as well (in a way that the
user could make use of the short form of the most used commands). I can think of two ways:

• keeping the optional flag

  • $ tatoeba-karini -d links

• aliasing the long positional argument

  • $ tatoeba-karini download links is the same as
  • $ tatoeba-karini d links

Any thoughts on this?

[lsrdg]

Closed on #38 .