Allowing a Maryland income tax deduction for an additional exemption of $12,000 for an individual who as of the last day of the taxable year is at least 65 years old or is totally disabled; reducing the amount allowed as an additional exemption by $1 for each $1 that specified income exceeds specified amounts; repealing a subtraction modification for specified retirement income of individuals who are at least 65 years old or are totally disabled; repealing obsolete provisions of law; etc.