Utils/Redis - Implement some Redis wrappers

Support for blpop, del, get, getset, incr, lpush
and set.
Utils/Semaphore - Distributed semaphore with Redis

Support for mutex.
To acquire the lock perform a BLPOP operation in Redis.
To release the lock perform a LPUSH operation in Redis.
Throttle - Main module for distributed throttling

Uses Redis to share throttle info accross scripts or servers.
Uses a mutex to guarantee atomic Redis operations across all
the places that use the same throttling limits.