Added extended logging support

Added verbose logging that details session check intervals.
Added debug logging that keeps track of requests received from
the client and responses sent to the client.
Changed Winston to use color when logging to the console.
Added "log_level" and "log_request_filter" fields to example config
file and config schema.
"log_level" determines what logs will be shown.
"log_request_filter" is an array of request types to filter out
from the logs (default "SENSOREVENT" and "TOUCHEVENT").