CLIMATE-530 converted GrADS plots to matplotlib and removed GrADs dependency in the preprocessing section
CLIMATE-530 - updated documentation 

- reflecting the removal of the GrADS dependency
CLIMATE-559 - removing the GrADSScript folder from the repo
Partially resolve CLIMATE-530-p1. Merge PR #140.
Resolve CLIMATE-530. Merge PR #141.
Resolve CLIMATE-559. Merge PR #142.