DeployTarget owner is now the head of the user queue rather than a separate attribute. By using Mongo $push and $pull to handle all queueing+dequeuing+claiming+unclaiming, we can avoid potential race conditions if two users try to become owner at exactly the same time (not that this has actually happened, but you know...).
Split DeployTarget time allotment into two attributes: defaultAllowedHours to change default for one DeployTarget (formerly allowedHours), and currentHourAllotment to change time allotment of current reservation only
fix auto-oust after timeout to work with new owner/queue structure. make negative currentHourAllotment signify a permanent reservation