kfre 0.1.7b

• Implemented exception handling for variables inside the kfre_person() function to ensure proper parameter validation.
• Added checks to ensure age, is_male, eGFR, and uACR parameters are supplied.
• Validated that the years parameter can only be 2 or 5.
• Ensured dm and htn parameters, if provided, are either 0, 1, True, or False.
• Added a check to ensure is_north_american is specified as either True or False.
• Added acknowledgements for key influencers whose exceptional work on end-stage kidney disease has greatly inspired the creation of this library.