create local data cache

[SBFRF]

Problem: Downloading can be slow
downloading data takes a lot of time if not on local network, this download time should be minimized. Data on the server also change from time to time (as bugs in processing are found or new, better processing algorithms are employed) so this should be updated from time to time. users likely work with short datasets and particular types of data.

proposed solution: Create Local data cache
create a local cache where data can be locally stored (efficiently).

options or things to consider

• using a conf file to determine the location of this cache
• update data from server on occasion (set to default but user update-able)
• maybe use pickle instead of lots of netCDF files, this could save space and time

[SBFRF]

@mfarthin here's an issue you might be interested in :)

[SBFRF]

It would be super cool to add a method into the class to save a pickle of the dictionary or some go.savemyStuff to all the data i've collected. @thesser1 thoughts?