call getpwuid, getgrgid and getpwuid only if NOT on Windows
gitignore generated files
use the standard Cwd module instead of PWD as a step to work on Windows as well
gitignore generated META files
master: whitespace fix in Utils.pm
master: avoid having 2 concurrent $htmlconfig
master: undef the config pre-reload (frees mem)
master: RAM usage for $cache
plugins: start implementing a new framework for plugins writing.

Munin::Plugin::Framework allows a much easier way to write new plugins
by abstracting the underlying protocol between node and master.

The idea is to have the plugins only declare what they want to have
displayed, eventually merging the code for configuration and
value-setting, and leaving it to the framework to generate the
configuration and fetch output.
procsys: implement a new plugin to replace entropy, open_files and open_inodes.

This new plugin uses the new Framework to create graphs for all the
sysctl-related data as a signle round-trip.

There is only one change compared to the previous plugins: open_inodes
produces a more meaningful graph of allocated and free inodes, rather
than the previous one that used a fake max value (as it was actually
the kernel's allocation).

Both open_files and open_inodes graphs now use areastacks instead of lines.
plugins: rewrite new multigraph plugins for using the Framework
procfs: merge load and uptime plugins.

The new plugin with the new Framework code makes it cleaner to just
have one place where most of the /proc files are read.
master: remove weaken on storable::read

6d62e6b0782ecfa0f4e0c2bec14434d675734962 introduced a weaken_config() sub, used
in munin_readconfig_storable().  It should not be needed, and some profiling
showed that it is a *huge* cpu eater.
master: remove auto_weaken()

Every weaken() should be done on construction time. Fixing it afterwards is
wrong, and might be dangerous. Let bug leaks happen and be fixed !
contrib: add a test for memory leaks
contrib: complete test with Storable dump/load

Test if Storable also saves the "weak" state.

Hint: it does.
Use a more efficient sort on the list of nodes

 - Cache the subroutine results, to improve speed when comparing.  More
   noticeable on a large number of nodes.
plugins: add doc about conntrack

As ilf noticed, then fw_conntrack plugin depends on the netfilter conntrack
userspace tools.

Updating the documentation as he suggested.

Closes: #1267
plugin/diskstats: fix negative stats, relax limits
plugins: use $PATH for external commands in shell