some improvements to the distribution ranges on the histograms
Merge branch 'develop' of https://github.com/agile-geoscience/modelr into develop

merging after fixing some distribution plots.
fixed too-wide-plot for one-panel case
added vertical exaggeration parameter to util and defaults, to replace the aspect ratio for plot scaling
fixed vertical exaggeration (working)
changed name of of vert_exag to aspect ratio
change default on aspect ratio
mergeMerge branch 'develop' of https://github.com/agile-geoscience/modelr