Hillsborough County Charter ; Revises number of commissioners on Hillsborough County Board of County Commissioners; revises territory of each county district; revises district reapportionment requirements; revises vote count requirements for enactment of ordinances & resolutions, for county internal auditor appointments & removals, for county administrator appointments & removals, for county attorney appointments & removals, & for charter amendments; revises process for appointing charter review board members & for proposing amendments to charter; provides requirements for transitions to single-member district & to 11-member board of commissioners; requires referendum.