add. UMPRegInput class to handle users whose reg date falls within the metric input dates.
add. REQUEST_VALUE_MAPPING structure that handles mapping from query_params vals to request vals.  Added _map_request_values method to perform mapping.
tag. UMAPI version 0.1.3-dev.
mod. package listing.
add. MySQL-python dependency to tox nose test environment.
add. some testing around UserMetricPeriod classes in users module.
add. initial user authentication hooks via flask-login extension.
add. method get_api_user to pull api users from prod.api_user table.
add/fix.  "by_id" flag to specify if param "user" is an id or name + additional query def to enable filtering by name/ref to "prod" db.
add. integrated query module definition to extract user data.
add. reauthentication view.
add. "login_required" decorator for each view.
add. secret key variable to settings for signing session cookies in flask-login.
mod. renamed request parameters "date_start" & "date_end" to "start" and "end" respectively
mod. "build_key_signature" convert request values to string when building each key
mod. move HASH_KEY_DELIMETER into data module, revise key.
mod. change "period_type" parameter to "group", both in metrics and in api
rm. lingering refs to "restrict" param
fix. how data is referenced and hashed for requests.
mod. use a hash of key signatures for all responses.