centralize logging into root logger

centralize logging into root logger

If we setup root logger correctly and have each
module logger propogate we shouldn't need individual
logger configuration

updates:
    lower paramiko to WARN level
    dispatcher/file.py was missing logging.handlers import
    purge all existing handlers and add our own handlers
    move everything back into yardstick/__init__.py so API can use it
    make _LOG_STREAM_HDLR global, so we can set loglevel on it whenever
    added api/server.py call to _init_logging
    removed old LOG_FORMATTER from cli.py
    only setLevel on yardstick logger

Change-Id: If000799590379d3407655a7d54378481a96ea3d4
Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>