add netCDF example

[nicholasbalasus]

Though this is not very distinct from some of the basic examples, I thought it might be good to have an example starting from a netCDF file (using NCDatasets from @Alexander-Barth). No worries if you don't think this is appropriate or if you'd like me to change anything. Thanks!

[Alexander-Barth]

very nice example @nicholasbalasus :-)

[asinghvi17]

Thanks for the example! I might want to change the title, since the current one semi-implies it's the only way to load data from netCDF. Otherwise this looks good.

[nicholasbalasus]

Thanks! If you let me know what you have in mind I can update it.