automatically determines appropriate db cluster given project id using public gerrit repo. fixes #57
removes duplicate implementation of get_project_host_map
fix. string formatting.
fix. pep8
mod. namespace specifier to 'all' for all namespaces
mod. JSON of time series response.
fix. cast timedelta args to int
mod. default interval length for time series to 24hrs
mod. use super method to call init method of parent class.
mod. use super method to call init method of parent class.
mod. use UserPeriodMetric map in revert_rate to define time periods.
add. two methods for logging on pool worker methods.
add. pre_process wrapper uses _param_types to auto assign attributes.
mod. refactor logging and parameter initialization.
merge. refactor logging and parameter initialization. Refactor bytes added and revert rate.
add. default _param_types for worker thread max defaults and logging
add. param logging to pre process, rename method to reflect more general behaviour
add. ensure uids are strings in preprocess
mod. retool apply_kwarg_defaults to assign_attributes.
mod. refactor metrics