What does this library?

At start, the library will focus in the oldest and most elementary branch of mathematics - arithmetic.

Basic operations are implemented to operate on integers and natural numbers.

Integers:
```
Z = {.. , -2, -1, 0, 1, 2, ...}
```

Natural numbers
```
N = {0, 1, 2, ...}
```

The library uses the positional notation
```
{ d[n], ... d[1], d[0] } (d[0] is less significative)
base
```

base is the number of unique digits including zero.

e.g. The number 15 in decimal notation (base 10) is represented as:
```
1 0
{ 1, 5 } = 1 * 10 + 5 * 10
10
```

Algorithms have access to the number representation using iterators.

```
{ !?!? , d[n], ... d[1], d[0] }
^ ^
end begin (iterators, pointers)
```

Basic math lib algorithms will use this abstraction.