realtime supervision

There is a time when I want to follow log activity in realtime with a monitoring tool. I had try nagios, zabbix and shinken but I never found what I need. So I decide to créate some code do that with shinken.
With my experience with nagios and shinken I've see that they can do a realtime supervision if we send them passively the state of what we want to supervise. But the problem with them is that their rule doesn't allow to process every passiv check result; they only process the last passiv check result for a service for optimization. Yes, this optimization is very important for perfomance but sometimes we don't need it(for log monitoring for exemple, we need that every line in the logs file is processed one by one).
This commit try to bring solution to avoid these optimisation sometimes we want to supervise something like log in real time. So it contain some code who work like that:
1- a receiver module like ws-arbiter get a passive check result for a sevice
2- The arbiter get the passive check result and execute the external command
          - If it is a check result for a normal service it will be process like every passiv check result
          - else, if it is a service what must be supervised in realtime(service with name starting with "log_" in this commit.It must be changed in futur like a item in service configuration) shinken will process it directly with some new function(in the schedulingitem.py and shceduler.py), so we the information is processed in real time.

Disadvantage:
        -It can reduce shinken performance

Advantage: 
       - We can use shinken to monitor something in realtime(specialy logs)
       - shinken can supervise a service in realtime in parallel to supervise other services with his native technics

 Futur: 
       - with these code, we can imagine to add some code with correlation logs technic. So, shinken will be able to have too more featurs and more useful for monitoring.


Where is these ideas? 
        I had a need to centralize all of our monitoring technics in one place and with one tool: logs monitoring, soft and hard monitoring,...
        I spend a time to learn nagios but I dicide to realize my idea with shinken(it write on python). My first realise is with shinken 1.4.1 but I've see that it's so easy to bring the code to shinken 2.0 so I put this commit with 2.0.


I use it for what? And how?
     I use it for realtime log monitoring. I've setup a rsyslog who centralise all of logs in my network and each time rsyslog get log it forward this log to a script who transform this log in passiv check result format that shinken understand and send it to shinken passively. With shinken webui I've write some code with tornado websocket, so I can see in realtime all log that shinken process in the shinken interface.