add a profiler for munin-node
Merge remote branch 'helmut/profile'
mpc: optimize HZ retrieval

As Brian De Wolf noted:

hz only really needs to be calculated once, so this line could be
moved up out of the loop, resulting in a likely unnoticeable
performance increase. :)
munin-profile-node.py: hanlde multiple connections
Merge remote branch 'helmut/profile'
mnc,mpc: move them to own repo