Updated GHCN_stations script to:

1) draw station location information from postgres database and perform merge/join query within database rather than r
2) add function to buffer region of interest to include stations outside region (to minimize edge effects)

Merging with bp/interp to use some of Benoit's code for precip interpolation

Merge branch 'bp/interp' into aw/precip

More updates to output plots

OR data preparation, initial commit for extraction of covariates from raster stack

OR data preparation task#363, modified code for ghcn to create a shapefile

Added initial version of LST_Landcover exploration (not finished). Also moved prior version of interpolation procedure (bayesian krig) into repository.

GHNCD station data selection using Postgres database, initial commit, task #363

GAM LST, added specific and general diagnostic measures (e.g.MAE) GAM+Kriging, task #364 and #406

GAM LST, adding lines to summarize samling RMSE using plots, task #409