Clear and Retry jobs by job class and exception

[jcasanovas]

With this, we can retry or clean only the jobs which a specific job class or job exception. If empty, it works as it used to work.

[coveralls]

Coverage increased (+0.5%) to 82.528% when pulling 7d9de03 on wuakitv:jcasanovas/clear-and-retry-jobs-by-job-class-and-exception into 717bc8d on resque:master.

[coveralls]

Coverage increased (+0.5%) to 82.528% when pulling 7d9de03 on jcasanovas:jcasanovas/clear-and-retry-jobs-by-job-class-and-exception into 717bc8d on resque:master.

[coveralls]

Coverage increased (+0.5%) to 82.528% when pulling 7d9de03 on jcasanovas:jcasanovas/clear-and-retry-jobs-by-job-class-and-exception into 717bc8d on resque:master.

[coveralls]

Coverage increased (+0.5%) to 82.528% when pulling 7d9de03 on jcasanovas:jcasanovas/clear-and-retry-jobs-by-job-class-and-exception into 717bc8d on resque:master.

[beltrachi]

Hi @rafaelfranca,

as you seem to be the one merging PRS here lately, how does contributions work here? Do we have to do anything to have this PR merged?