vastly improved all-plot.R
(a) better color scheme;
(b) using POSIXlt datatype to decompose epoch time so no more hard-coded starting times/days for data input file
(c) plot view is controlled by truncating vector of plotted values instead of truncating the visible window
(d) weekends are now shaded based only in visible window and based on time, not points in the dataset
(e) added support for storage resource usage monitoring
(f) added separate vectors for styling the line width, line type