Issue #2911527 by harsha012, b_sharpe, Chris Burge, Manav, jibran, Waldoswndrwrld, christinlepson, vacho, mttsmmrssprks, nicholasThompson, Wim Leers, othermachines, Sutharsan: Allow dashes in Styles dropdown's element names

Issue #2725039 by rajeshwari10, brentgees, neha.gangwar, andrewmacpherson, kristindev, joginderpc, surbz, mayurjadhav, manish-31, mttsmmrssprks, bandanasharma, cilefen, xjm, alexpott, lauriii, Cottser, aburrows: Add README.txt to Seven theme