parameterize the service class

Dennis:

I made some changes that add parameters to the service class.

With the changes to parameters, one can now do either of the following:

```ruby
monit::service {
  "tomcat-server.rc" :
    content => template( "tomcat/tomcat.monit.erb" );
}
```
``` ruby
monit::service {
  "puppet-client.rc" :
    source => "puppet://modules/puppet/puppet-client.rc";
}
```

This allows users to deploy their own configuration files without making modifications to the source code of your module.

Thank you for starting this module!

Best,
Matt