Provide UI to limit file download listing and wget generation by time range. This request came from an end user. There is consensus amongst stakeholders this is a useful feature.

From email (stacyjackson@berkeley.edu):

> A few enhancements would make things easier (or perhaps these already exist & I just haven't found them yet):
>
>
>
> - Limit # Years: I only want to download the data up to 2100. There doesn't seem to be an option to limit the time range of the download, and this is going to result in me downloading an enormous amount of data that I don't need (& don't have space to store).
This option will be forthcoming. In the meantime you can select a subset of files to download. The times are indicated in the filenames.
>
>
>
> - Multiple Variables: I'm doing an analysis that will involve comparing several variables across models & scenarios. I would like to be able to only see those data runs for which all of my variables are available. At present, it seems like I can only select 1 variable at a time.
An option to select several variables is also forthcoming, but it won't do logic such as *only* models for which A and B and C are available. If you ask for A and B and C, you'll see all data available for those variables, which in some cases will be incomplete.