HALLOWELL — A developer is moving ahead with the creation of a master plan for the Stevens School property now that city officials have voted to allow ordinance changes for the project. Matt Morrill’s attorney, Tom Federle, said the next step is the filing of the master plan, which he expects to happen in September. “Once the master plan is approved, (Matt) will be in a position to begin applying for development approvals,” Federle said. Federle said Morrill, who purchased the property in April, is continuing to make improvements to the Baker Building, which already has one tenant and should have another soon.