Add version command to nmapps cli utility and move the rst files so that setup.py can find them.
Move nmapps.util to nmapps.tool.
Fix MANIFEST.in to include sphinx files (rst and conf.py).
Continue work on the framework.

* Add nmapps.app.Command class to represent nmapps.app.CommandApp
  commands.
* Add nmapps.app.AbstractFile to start work on abstraction over
  input/output streams/files of an application.
* Add nmapps.utils.PrefixDict class to allow for command shortcuts in
  nmapps.app.CommandApp
* Make small improvements to nmapps.fs.
* Add some docstrings.
* Possibly other stuff I don't remember.