macro processor: allow colon-separated arrays as command-line defines

colon-separated command line arguments such as
```
dynare <<.mod file>> -DA=1:5 -DAA=1:2:5
```
are now translated as:
```
@#define A = [1, 2, 3, 4, 5]
@#define AA = [1, 3, 5]
```

(cherry picked from commit 6d1c2ca8)