Add support for orchestration "strategy" and "filter"

[Phil Winder]

Applications have different requirements to orchestrate the application. For example, some applications need to spread across hosts, whereas others want to maximise instance usage.

To do this, follow the precident set by Swarm to implement a Strategy (i.e. how to rank/sort hosts) and a filter (how to position).
https://docs.docker.com/swarm/scheduler/strategy/
https://docs.docker.com/swarm/scheduler/filter/

• Implement configuration option mesos.resources.strategy
• Implement configuration option mess.resources.filter [#17]
• Add strategies {spread, binpack, random}
• Add filters {executorName, ...}*

*See swarm filter page for more options. My main use case is to only allow a single task on each host. So I would enter something like:
mesos.resources.filter: executorName!=elasticsearch-task