master: add "use_default_node"
travis: adding preliminary test for rrd
travis: be root for rrd install
travis: fix rrd tar extract
travis: customized rrd build
travis: be root to install rrdtools.
travis: install the Perl deps in the Perl dir

As the rrdtool ./configure said :

	By default the rrdtool perl modules are installed together with rrdtool
	in $prefix/lib/perl. You have to put a 'use lib qw($prefix/lib/perl)'
	into your scripts when you want to use them. When you set this option
	the perl modules will get installed wherever your perl setup thinks it
	is best.
travis: add some whitespace
travis: optimize for compile times
cgi/graph: Set RRDCACHED_ADDRESS during each request

RRDCACHED_ADDRESS is normally set during graph_startup. However
CGI drops all external environment variables and replaces them
with CGI variables. We have to set RRDCACHED_ADDRESS each time
so rrdgraph will use it and flush data correctly.
node: Only spoolfetch send 5 samples per service

This enables to not overwhelm the munin-update when there is big backlog
to handle.  Note that this is only a 5x speed increase, so a backlog of
5 hours is fully sent in 1 hour.

This value is _very_ conservative, but a new config value is planned in
the devel branch. Here in stable-2.0, it's a perfectly valid strategy.
Merge remote branch 'pull/213' into stable-2.0
Merge remote branch 'pull/232' into stable-2.0
Merge remote branch 'pull/119' into stable-2.0

Conflicts:
	common/lib/Munin/Common/Config.pm