v1.8.0

New features:
- yC to copy git config command to set user name and e-mail address
  commit 8777d6bdff699adf94a2c6fa8a4f9d55fd029af9

Help:
- mention tig
  commit a88bac3ab4105cdb0f947f163228187daaf01f72
- documented that line numbers are not available with --word-diff in more places
  commit 900c3b02a3c897046b5720747e02739b8aa7f00c