Update index.rst

Added syntax for WSGI service through UNIX domain sockets
Merge pull request #40 from csingley/patch-1

Update index.rst
add a url_prefix adjustment that behaves much like paste prefixmiddleware (to avoid needing to explain paste prefixmiddleware, which avoids needing to explain pastedeploy, which avoids needing to explain pipelines, and so forth)
fix merge conflicts
add url_prefix docs
prep for 0.8.6