Use author initials instead of names

[augustohp]

Given we are pairing on a git repository with a history, we can use all author names available on the history (and the ones already provided in the pairing standard) to identify which authors we want to pair with.

Given current authors in the repository are: Augusto Pascutti, Ivo Nascimento, Anderson Pereira and Antonio Pinto:

$ git pair in
Local authors name now are: Augusto Pascutti + Ivo Nascimento

$ git pair ap
There are two authors which match "ap" initials:
    ape) Anderson Pereira
    api) Antonio Pinto

Re-issue the command with an unique initial.

Note that although ap also matches Augusto Pascutti we should identify and eliminate him as a possible pair given he is the committer of the session and therefore a constant on the pairing session.