Add support of phpredis

Use phpredis if installed, else fallback to redisent
Fix typo in namespace name
Fix Redisent fallback
Merge remote-tracking branch 'parent/master'
Add support for Redisent
Add monolog as Composer requirement
Edit Failure logging to auto-expire, and rename key to a more searchable one
Use Monolog as log engine, and composer autoloader for autoloading
Redirect all events to Monolog
Update ignore
More structured Job.toString()
Use STDOUT for logging if Monolog does not exist or is not configured

Fix start event logging
Code refactoring
Update Composer file
Update documentation
Update Doc with install and usage instruction
Output to STDOUT if no log Handler is defined
Update travis
increase default socket time out to 5

To avoid Redis lost connection exception
Avoid persistent connection to redis because of timeout bug