ntp_: rewrite plugin to support IPv6

Closes Debian bug #558800 and Munin trac ticket #775
master/html: implement lazy loading for images

It is done using the lazyload library

(http://www.appelsiini.net/projects/lazyload)
html: Add a "loading circle" on lazyload
Reduce logging at INFO level in munin-graph

Improves Trac ticket #1251.  Reduces normal log lines by 66%.
hp2000_: New aspect for port based metrics.
Merge branch 'lazyload' into devel
Merge pull request #58 from kenyon/ntp-rewrite2

ntp_: rewrite plugin to support IPv6
tests: fix RRDs deps in unit testing

RRDs.pm does exist in travis. We do not really use it anyway.
tests: fix warning about potential typo
tests: Net::Server dep was missing in .travis.yml
tests: Module::Build is duplicated in .travis.yml
tests: rm the OS::get_fq_hostname() test for "."

The Travis-CI VM do not have any "." in their FQDN.
Merge pull request #67 from steveschnepp/fix-travis

Fix travis builds
tests: Use only IRC notifications for TravisCI
Merge branch 'travis-notify' into devel
iostat and irqstats include/exclude list

- include_only config option for iostat
  one can set a list of devices which will be monitored

- skipdevs option for irqstats
  specified devices will be skip from monitoring
  it's very handy on citrix xenservers with many VMs
asterisk: introduce a new, multigraph-capable plugin for asterisk.

The new plugin replaces all seven of the old plugins, with a single,
common and collapsed configuration, by drawing multiple graphs with a
single set of transactions to the server.

It also supports autoconf (which was not supported by the old asterisk
plugins), and wildcard/virtual node mode, when monitoring a remote
server.
apache: replace old Apache plugin with new, multigraph-capable one.

The new apache_status plugin provides the previous three graphs as
multigraphs, with a single request to Apache.

It also works as a virtual-node plugin, by querying a remote server.
squid: introduce new Squid plugin to replace the old ones.

Again this plugin uses multigraph and supports virtualnode, and
collapses the five previous squid plugins, reducing the number of
requests coming in for the proxy itself.

Neither output nor configuration ports directly to the new plugin,
unfortunately, but it does allow for saner output and store (in
particular killing cdefs).
plugins: introduce a readfile() function to Munin::Plugin

Especially on Linux where most of the information for the system
status data is read out of /sys or /proc, it's easiest to have a
convenience function that reads a whole file in a scalar variable.