bring mean climate pr codes into repository

[gleckler1]

@msahn @lee1043 It will be good to bring the progress to-date into repository so that we can work together to refine these and make some of the quasi-operational, ie., readily for repeat use.

• [x] Folder with codes associated with regridding tests
• [x] Folder with basic matlab plots done to date, e.g., bar charts, clim time series and TD
• [x] Folder with code to prepare observational masks

[gleckler1]

@msahn @lee1043 What I'm thinking is that it would be good to put here the codes you wrote to produce json and nc results that were later compared to demonstrate the impact of regridding in different situations. Examples include the maps and difference maps based on different regrid methods, the codes used to produce bar charts that showed the difference between regrid methods, and Taylor diagrams. Maybe its better to have all of the codes related to this regrid testing in the same folder, including plotting codes.