Visibility Modes should apply to clear all bookmarks

[cheoAlejo]

It could be nice if we could clear all bookmarks only in a file, or by project, or globally, exactly like the "goto" command works for visibility modes. Other than that, it's a great plugin.

[gwenzek]

My pull request uses the 'getVisibleBookmarks' method to choose the bookmarks to clear.

[cheoAlejo]

mm, i haven't seen the pull requests, thanks.