Add open_files capability to ejabberd_resources_

It appears that erlang port is not bound to an OS file very often.
Thus "ulimit -n" is moved to a separate graph and lsof/fstat is used as
a backend to count the number of files open.
Add support for ZFS On Linux
Removed deprecated hadoop command for hdfs
Made hdfs user configurable (FIXME: user plugin.conf)
better way to do it
updated to user the perl munin module and user config from plugin-conf
don't collect/send redundant data to munin
Merge pull request #403 from dotdoom/master-ejabberd_resources_-file-descriptors

Add open_files capability to ejabberd_resources_
Adding simple Bash script plugin to read information also from Netatalk v3.
Merge pull request #411 from tuxis-ie/master

Add support for ZFS On Linux
Merge pull request #414 from tsaavik/master

Updated to work without using deprecated hadoop command and allows setting of hadoop admin user via plugin-conf
Merge pull request #416 from otaviof/master

Netatalk v3
fork the mysql_connections plugin to add per-user support
limit to ten the number of users by default
cosmetic fixes
reorder graph to, hopefully, fix stacking
limit and sort the config entries the same way as we sort values, based on values
overhaul graph display: remove total, make "current" the "limit"

i did this because I can't figure out how to *not* stack the lines
after the areas. furthermore, removing the limit is essential to have
a proper resolution in the display.
cosmetic
Stub for juniper plugin
Fixed wrong path to munin-node config file in doc