Documentation browser

Gracle needs a good documentation browser. David Murray is working on such a thing (called Climfo). It will be an ESA-based browser for files in the GNU Info format (the output of Texinfo). Climfo will be good enough to start with.

Eventually, We might want a more sophisticated browser that can navigate in a graph of documentation nodes. Since Gracle uses universal persistence, there is no need to define a documentation format in the form of sequences of bytes. The documentation authoring tool would simply generate nodes of this graph instead.