Minor fix in task queues

Fix taskQueue to allow repeat calls to remove a task

Task Queues

Fenzo now supports task queues and introduces a scheduling service that iteratively loops over the queue to launch them, repeatedly trying to assign resources to pending tasks. A tiered queue is introduced, with other queue implementations possible.

Make Mesos offers available to constraint evaluators

Constraint evaluators can further optimize task placement by inspecting the Mesos resource offers that comprise the resources being assigned. This especially helps for inspecting the offers for attributes that are not directly supported by Fenzo at the time. Constraint evaluators receive target host/VM as VirtualMachineCurrentState object, which now has a method getAllCurrentOffers().

Support for scalar resources

Add support for tracking and assigning any scalar resource.

This does require changes to the interfaces TaskRequest and VirtualMachineLease. Therefore, users will have to add implementations to the new methods in these interfaces.

Expose disabled until time for VMs from TaskScheduler

VMs can be disabled and enabled for picking resources to assign from. However, the time until which a VM is disabled is not visible. This PR exposes this information via VirtualMachineCurrentState interface.

Support for initializing assigned custom resources

Redo after gradle and netflixOSS upgrade.

Support for initializing assigned custom resources

Merge pull request #80 from rspieldenner/travis

Travis conversion