Updated gramox_calc.py
Updated gramox_calc.py

Added input option of taxonomic level, where user can provide the
taxonomic level of the data being processed. This script now supports
genus as well as species level data processing.
Also, updated the output file content to not contain a 'source' column.

akshayparopkari/kadambari,akshayparopkari/kadambari,akshayparopkari/kadambari