Providing for the submission to the qualified electors of the City of Philadelphia a proposal to adopt a tax on real property dedicated for the sole purpose of funding public libraries; fixing the date of a special election for such purpose; prescribing the form of ballot questions to be voted on; authorizing the appropriate officers to publish notice and to make arrangements for the special election; and amending Chapter 19-1300 of The Philadelphia Code, entitled "Real Estate Taxes," to provide for the tax and to provide for a corresponding adjustment in the existing real property tax rates — Open Common Ground