Handling Max recursion depth

[granrothge]

Expose Max Recursion Depth to the dictionary read by reduce_data_to_MDE.py

If there is no entry in the dictionary or if it is set to None it should use a default value of 6.
Should we also expose the Min and Max Values?
If I understand the MD data structure right it would mean the max number of bins would 5^Max recursion Depth between the min and max values. So exposing these would allow to relax the number of bins further if they are looking at a smaller portion of their data. The default should be how it is defined now.