clean up usage
core: Machine#with_ui
core: Prefixed UI only requests bolding if not specified at instance-level
core: Environment#lock tests
core: fix Environment tests
core: Ui#dup works properly
core: Ui::Prefixed can take prefix_spaces option
core: Ui::Prefixed values instance-level opts
providers/virtualbox: config to skip guest additions check
Fixing ssh_config proxy_command is not included
Remove website/ dir from gem [GH-2951]
Merge pull request #2950 from elyast/master

command/ssh-config: Fixing ssh_config, proxy_command is not included
Update CHANGELOG
Merge pull request #2948 from gnawhleinad/master

command/*: clean up usage