Docs request: mention log verbosity controls in readme (`set_debug_level` and `set_global_debug_level`)

[mxkpp]

Hello, thanks for supporting this simple route for reducing verbosity of logs:

from hecdss import HecDss
HecDss.set_global_debug_level(0)

I would recommend adding mention of set_debug_level and set_global_debug_level to the readme, including some examples of the effects of the scale from 0 to 15. I am not experienced enough with this library to describe it myself, sorry I am not able to open a PR myself with adequate notes on this topic.

Thank you!

[mxkpp]

Hello @ktarbet. A colleague of mine referred me to the C headers and related official documentation, and after reviewing those I've opened #101 with some notes on this topic. Thank you for these tools!