Rename parser:  parse_jdoc() -> jdoc()
Rename: to_tree -> to_dump
Use the writemime() framework to output JDoc files.
Include the original (raw) docstring in the documentation object.
Bugfix: Use the IO stream properly in writemime().
Update documentation.
Reorganize code, so the API documentation comes out first.
Bugfix: Move DocNode definition to JDoc.jl

Also move the export of jdoc and DocNode to JDoc.jl
Merge backend.jl & frontend.jl, update documentation and move exports to JDoc.jl
Rename help -> jhelp to remove the unsightly warning.
Minor: Add a newline after the 'dump' outupt.
First implementation of the "jdoc" program.
First README file generated from the source code.