New Bookmark scope capability

[mpniel]

It would be great to be able to define the bookmark scope as follows:
- Local: the current file, current behaviour.
- Global: all open files; all the bookmarks defined in all open files will be available.

Add it as a new setup definition in the preferences window.

[lwidener]

I agree with mpniel. I would like maybe another bookmark that was global in scope so I could jump from a bookmark in one file to a bookmark in another file in the same workspace. Also to have a method of clearing all the global bookmarks to be ready to work the next issue.

[Quick]

I agree with the second part of the previous post. I would like the ability to clear all bookmarks in all open files (since I can mark all in all documents).