Improve handling of string parameters

This should not be an error. Display tall plot instead? Plot only first N unique?

https://hapi-server.org/plot/?usecache=false&usedatacache=false&server=http://hapi-server.org/servers/SSCWeb/hapi&id=ace&parameters=LT_GSE&time.min=1997-08-25T17:48:00.000Z&time.max=1997-08-26T17:48:00.000Z

Could modify to recognize that this is a time.