_arch.txt includes blank lines which lead to errors

```
src/matlab/__init__.py:
with open(arch_file, 'r') as root:
    [arch, bin_folder, engine_folder, extern_bin] = [line.strip() for line in root.readlines()]
```

blank lines are not ignored in this code which are created by default from MATLAB.
`[line.strip() for line in root.readlines() if line.strip()]` would fix it.