Towamencin officials have rolled out a budget for next year.   The spending plan totals almost 13-million dollars and does not call for a property tax increase.   Sewer rates will remain the same too.   The proposed budget also continues the homestead and farmstead exemptions that allow the owners of residential property to shield the first $59,000 of the assessed value of their home from taxation.   The proposed budget is available for public inspection at the township building on Troxel Road.