Adding --skip-editor and --notes to bookmark command.

These patches add two options to the bookmark command : 
  - `--skip-editor` prevents the editor from being launched and directly save the bookmark.
  - `--notes` sets the notes field of a bookmark from the command line.

They aim to make `jot bookmark` usable from inside a script, without requiring human intervention when bookmarking. This allow to create others interface to get the values, which use then jot to save it (I am thinking of a uzbl bookmarking script based on jot).