Differences with matplot++

1. Example #9 in :doc:line plot 3d: random numbers are not used.

2. Several examples in :doc:loglog: two lines are shown instead of one.

3. Last example (with alpha) in :doc:image matrix and :doc:scaled image.

4. Example 2 and 3 in :doc:polar histogram.

5. Example 4 in :doc:polar scatter.