Update reference documentation

It's now hosted at readthedocs.org, so I've updated the link and removed
our copy of the documentation.

Kind of part of #283.
Update installation guide from .rst
Update title
Add nipapd v0.23.2 to debian stable & test repo
Add v0.24.0 to debian apt testing repo
Add v0.24.1 to debian apt testing repo
Add v0.24.2 to debian apt testing repo
Add v0.24.3 to debian apt testing repo
Add v0.24.4 to debian apt testing repo
Add nipap-whoisd to debian testing repo
Change Makefile to copy from testing to stable

Fixes #483.
Add v0.24.4 to debian stable repo
Add new style documentation