An Act amending the "Tax Reform Code of 1971," approved March 4, 1971 (P. L. 6, No. 2), further defining farming; further providing for the taxation on the sale of horses in certain circumstances; exempting feed for horses and rodents; further providing for imposition of the personal income tax, for estimated tax and for agreements with other states with reference to the income tax; redefining "average net income" and "capital stock value"; providing for the exclusion of construction of hydroelectric generating facilities from the tax on utilities; further providing for the tax on mutual thrift institutions; and making a repeal.