ggRandomForests: CRAN Christmas release V1.1.2

Add package vignette "ggRandomForests: Visually Exploring a Random Forest for Regression" Add gg_partial_coplot, quantile_cuts and surface_matrix functions export the calc_roc and calc_auc functions. replace tidyr function dependency with reshape2 (melt instead of gather) due to lazy eval issues. reduce dplyr dependencies (remove select and %>% usage for base equivalents, I still use tbl_df for printing) Further development of package vignette "Survival with Random Forests" Refactor cached example datasets for better documentation, estimates and examples. Improved help files. Updated DESCRIPTION file to remove redundant parts. Misc Bug Fixes