This function should not be used directly,
only inside .plot_CoxPH_RNAseq_TCGA() function.
side effects: forest graph showing the relation between survival of TCGA patients and EIF expression in their tumors from regression model
.forest_graph(data, output.file, plot.title, x.tics, x.range)output dataset generated from .univariable_analysis() or
.multivariable_analysis() function
output file name
title name of the forest graph
tics for x axis
range for x axis