Add xml "metadata" file to csv tabledap outputs for arc

[kknee]

also, so far the regular .csv format is preferable to the .esricsv format, so if you add a filter please leave both options

[kknee]

also, add cdm feature type to xml file

[kknee]

bumping this...need sooner rather than later as i need to update my code accordingly and would like to get new versions to roy next week

[kwilcox]

Need to add timesteps and timerange to the XML

[kknee]

and variable names...