Merge branch 'master' into v2.0

Conflicts:
	.gitignore
	.travis.yml
	CHANGELOG.md
	README.md
	guard.gemspec
	lib/guard.rb
	lib/guard/guardfile.rb
	lib/guard/interactor.rb
	lib/guard/notifier.rb
	lib/guard/notifiers/notifysend.rb
	lib/guard/notifiers/rb_notifu.rb
	lib/guard/version.rb
	spec/guard/dsl_describer_spec.rb
	spec/guard/dsl_spec.rb
	spec/guard/guardfile_spec.rb
	spec/guard/notifier_spec.rb
	spec/guard/notifiers/gntp_spec.rb
	spec/guard/notifiers/notifysend_spec.rb
	spec/guard/runner_spec.rb
	spec/guard/watcher_spec.rb
	spec/guard_spec.rb
Backport e8d1c4adf91
Update man
Backport 3fdf9e5c77cc
Backport #450
Backport 7b12492e61