just minor tweaks to code comments

removed placeholder cruft from flowdir correlation plots

revamped aspect/flowdir boundary assessments to use circular statistics

added multiresolution spline fused layer as terraflow input

added GRASS commands to run terraflow on Canada boundary DEMs

added R code to create various boundary assessment figures

added GRASS/R code to run/compare flow analysis on Oregon test area

added GRASS terraflow code plus basic R diagnostics for 60N test case