Property taxes will stay steady in Towamencin next year.   The township supervisors Wednesday night adopted a budget for 2012 that totals just over $16,000,000 but does not ask homeowners to dig any deeper into their pockets.   Sewer rates and pool membership fees will go unchanged as well.   The budget also continues a homestead exemption that allows qualified homeowners to shield $59,000 of the assessed value of their property from taxation.   The non-uniformed employees of the township will be going without a pay increase again next year.