Fixed typo
Remove unused files
Simplified Daemon class
Added old rrdtool backend and renamed module hdf5-collector to collector
Added `--buffer-size` option for collector to define the maximum number of counters that colmet should queue in memory before pushing it to output backend
Used zeroMQ eventloop and zmqstream
update requirements
remove TODO list
remove old NOTES
update changelog
Dropped rrd backend because it is not yet working