Keep the URIs DRY and add suffix -uri
Reword the README

 * Keep the URIs dry
 * Replace "render" with "convert"
 * "Upgrading" is now a sub-section of "Installing"
 * Move the sentences that encourage contribution in the "Contributing" section
 * Rewrite the "Using custom templates" section
 * Add a note on the benefit and downside of using Linux package in "Installing" section