Bug: Wrong conversion ToUint64 about cast

[abukosek]

The problem appears to be in the ToUint* functions and was introduced in commit 2b0eb0f724e320b655240e331aef36d1175986c2.

Previously, the code was:

	case string:
		v, err := strconv.ParseUint(s, 0, 0)
		if err == nil {
			return uint(v), nil
		}
		return 0, fmt.Errorf("unable to cast %#v to uint: %s", i, err)

But in that commit it was replaced with:

	case string:
		v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
		if err == nil {
			if v < 0 {
				return 0, errNegativeNotAllowed
			}
			return uint(v), nil
		}
		return 0, fmt.Errorf("unable to cast %#v of type %T to uint", i, i)

All ToUint* functions have this bug (bad copy&paste?).

The previous code should be restored -- the only new addition is trimZeroDecimal(s), which can be added to the old code as well.
The check for negative values is also not needed if using ParseUint as before.