Document jedi.replstartup usage
Setup intersphinx module for linking Python doc

For example, :mod:`readline` links to the corresponding page.
Document utils.setup_readline
Add utils.JediRLCompleter
Improve JediRLCompleter for minor cases
Determine readline delims programmatically
Document JediRLCompleter
Merge pull request #222 from tkf/replstartup

Improve $PYTHONSTARTUP support