Includes accurate setup instructions.

The current (real machine) setup instructions were somewhat vague and
didn't work for me when I tried to set up dxr. This commit updates
them addressing all the problems I faced so that it's clear what needs
to be done to get it to work.
Updates README as per feedback.
Wrap lines to around 79 cols for consistency with the rest of the readme.

Also add a note about how to install TriLite globally.

Bump minimal Python version in deployment.mkd to 2.6, as we haven't tested on 2.5 in a long while, and that's years out of date.
Merge Noufal Ibrahim's better production setup instructions. Fix #129.