granovagg.ds plot is reversed

The help document states: is an n X 2 dataframe or matrix. First column defines X (intially for horzontal axis), the second defines Y.

However, when running this code it appears the first column is the Y coordinate, and the second is the X:

```
df <- data.frame(X = rnorm(10, 5, 1), Y = rnorm(10, 0, 1))
granovagg.ds(df)
```