I added a getTaskPriorityColor function to the ManiphestTaskPriority class which returns the color set in the maniphest config for the given priority.

This is in preparation for a change to arcanist which will allow it to display the priority color (if it is a supported color) upon running arc tasks.

Fixed some linting issues

Invoke the maniphest.info method from conduit and ensure that:

• The priorityColor property is given in the json
• the priorityColor property is set correctly