The Inverness Foundation and the Marin County Free Library have agreed to a new five-year lease for the Gables, the building that has housed the library’s Inverness branch since 1986. The foundation will earn $1,400 a month in rent, with an annual three-percent increase—less than its received in the past two years. From 2002 to 2007, a lease agreement provided the foundation just $650 a month; when that lease expired, the county began to pay…