gam fitting, adding option to run fitting with starting list of k values and clean up

gam fitting diagnostic, degug functions, cleaning up of code

gam fitting diagnostic, adding rmse, mae and other metrics as well as wrap function to run fit at different

gam fitting diagnostic for low station count, adding function to collect k-index diagnostics

initial commit, script for gam fitting experimentation - fitting in low stations area

contributions of covariates and methods paper: revisions- major clean up of code and production of figures for submission of revisions

contribution of covariates and methods paper: revisions- breaking down significance and accuracy of LST by month

contributions of covariates and methods paper: slight changes to function script for LST analyses

contributions of covariates and methods: revisions -adding analyses for LST contribution

contributions of covariates and methods paper: revisions-change of residuals in function of elev and use of lattice package