Change default storage.local.path mentions

Update docs regarding `keep_common` modifier.

Set up continuous deployment

Provide RSS feed for blog posts

Docs adjustments with latest changes

Add RobustIRC as natively instrumented software

Add blog post about service discovery

Indicate WITH keyword as optional in alerting docs.

Fix run-on sentence, improve increase() doc wording.

Add initial documentation for the alertmanager.

Add a new section for alerting so it's all together,
and move the alerting rules over there.

Document increase() function.

Improve wording in the naming section even more.

This should have been part of
https://github.com/prometheus/docs/pull/95, but somehow I missed to
commit it.

document caveat about combining sum and rate

As per https://groups.google.com/d/msg/prometheus-developers/wfGhGkDcZ3Q/SXv4aDGgKY8J

Sanitize and uniquify in-page anchors properly.

Improve Configuration / SD documentation.