Nevada County's municipalities have taken a hard line on medical marijuana dispensaries this year. City councils in Grass Valley and Nevada City, as well as Nevada County supervisors, all either have passed or extended moratoriums on medical dispensaries in the past year. Officials are now keeping a close eye on Proposition 19, which would allow the possession of up to an ounce of marijuana for recreational use, and allows local governments to control the sale of marijuana and tax the revenues. The initiative appears on the Nov. 2 ballot.Grass Valley doesn't have any zoning that expressly allows a medical marijuana …