multi RingBuffer test ver0.5

A Builder thread reads data in all RingBuffers
multi RingBuffer test ver0.5

set Nconn =< MAX_RINGBUF
Nconn of Collector_thread will be generated.
They write their own RingBuffers and
A Builder_thread automatically reads them.

usage:
  $ g++ -pthread MultiRingBuf.cpp RingBuffer.cpp
  $ ./a.out
DAQ_NEVENT is defined
DAQtimer ver1.0

simple measurement of ReadFreq