Refine pydoc of standalone.py

- Refine instructions for TLS support
- Add underlines to headings
- Replace examples to ones with PYTHONPATH env setter
- Add note about how relative paths passed to TLS related parameters
  are resolved

R=yhirano@chromium.org

Review URL: https://codereview.appspot.com/98800043

git-svn-id: http://pywebsocket.googlecode.com/svn/trunk@798 4ff78f4a-9131-11de-b045-6380ec9940d4