Approve an On-Call Master Contractor Services List for Public Facilities for Fiscal Year 2007/08 and Authorize the City Manager or His Designee to Execute Contracts with Three One-Year Renewal Periods for 1) Heating, Ventilation and Air Conditioning (HVAC) - Small Tonnage Service with: A) Mielcasz and Association in an Amount Not to Exceed $50,000 per Contractor