Typo

[`Matrici` -> `Matrice`](http://dexonline.ro/definitie/matrice)

Sper că am fixat peste tot:

```sh
$ grep -ri 'Matrici' .
./.git/COMMIT_EDITMSG:Fixed typo ("Matrice" instead of "Matrici").
./.git/logs/HEAD:ba0339aa00b07a593a78e778fdb33a7108d72bda 463476c9484a0553fe65333fed0859b7667f080d Ionică  Bizău <bizauionica@yahoo.com> 1418221156 +0200	commit: Renamed files ("Matrici" -> "Matrice").
./.git/logs/HEAD:463476c9484a0553fe65333fed0859b7667f080d 536a1211ed1ebb606540ac6459eca9c5cac7e5f6 Ionică  Bizău <bizauionica@yahoo.com> 1418221325 +0200	commit: Fixed typo ("Matrice" instead of "Matrici").
./.git/logs/refs/heads/typo:ba0339aa00b07a593a78e778fdb33a7108d72bda 463476c9484a0553fe65333fed0859b7667f080d Ionică  Bizău <bizauionica@yahoo.com> 1418221156 +0200	commit: Renamed files ("Matrici" -> "Matrice").
./.git/logs/refs/heads/typo:463476c9484a0553fe65333fed0859b7667f080d 536a1211ed1ebb606540ac6459eca9c5cac7e5f6 Ionică  Bizău <bizauionica@yahoo.com> 1418221325 +0200	commit: Fixed typo ("Matrice" instead of "Matrici").
$ grep --exclude-dir=".git" -ri 'Matrici' .
```