Hyperbole Buttons

   1. "Buttons" are a way to associate some kind of text with some
      emacs lisp to run.

     1a. You move the caret over text and press an "action key" to
         trigger whatever a button does.

     1b. "implicit" buttons involve attaching a regexp matcher to a
         list. Each matcher in the list are tried and if they match
         some text, they run some lisp.

       1b1. An example of an implied button is "<@ 1a>" which means to
            match outline item 1a in the current file. Another is
            "bug#800815" which might launch a web browser or download
            an emacs buffer showing details of a particular bug.

       1b2. By default hyperbole also turns identifiers in programming
            modes to buttons; when pressed it looks the identifier up
            in the nearest tags file.

     1c. "explicit" buttons are text that show up "<( like this )>"

       1c1. there are button files for each user and also optionally
            in each directory that associate some text with one of
            these button names.

     1d. "global" buttons are named macros, basically. These get
         activated through some menu or keystroke and then mentioned
         by name.

   2. mutiple kinds of links

     2a. you can link directly to koutline nodes, you can link to
         particular files, you can also link to specific rows inside a
         named text file. you can link to text searches within
         specific files (ex. for when contents moves around and you
         can't leave anchors in the file to link to.)