Add support for other program types

I am hoping to add support for other supervisor program types like [eventlistener](http://supervisord.org/configuration.html#eventlistener-x-section-settings) and [fcgi-program](http://supervisord.org/configuration.html#fcgi-program-x-section-settings). 

I have implemented this in a generic manner to allow for the eventlistener and fastcgi specific params to be appended to the .ini file as arbitrary key/value pairs. This provides flexibility without cluttering the `supervisor::service` attributes with program specific settings. 

Here is a basic example that uses the memmon command from the [superlance](http://superlance.readthedocs.org/en/latest/memmon.html) plugins:

```puppet
supervisor::service { 'memmon':
  command => 'memmon -a 200MB -m someone@somewhere.com'
  type => 'eventlistener',
  ini_append => {
    events => 'TICK_60',
  },
}
```