Initialisation code on jobs

[Iván Loire]

Be able to define onStart actions for jobs (for initialisation code, cron, etc).

Ex: instead of:

module.exports = function(config, dependencies, job_callback) {     
    job_callback(null, {});
};

have something like this:

module.exports = {
  onStart: function (config, dependencies, job_callback){
    //this is executed once 
  },
  onRun: function(config, dependencies, job_callback){
    //this is executed every job interval  
  }
}

[Iván Loire]

and eventually:

module.exports = {
  dependencies: {
     "cron" : "0.0.x"
  },
  onStart: ....
}

[Iván Loire]

We can specify dependencies now in a per package package.json and we can execute code only once by setting a flag in the job, so we can close this issue