Improve presentation of test results from buildpack

[Ian Culverwell]

ROPP5.0 beta tester Luiz Sapucci commented that the plethora of images that pop up when running the package tests implicit within buildpack, is a bit confusing. We think he has a point.

I suggest that as each figure is produced, it and its corresponding reference image are displayed on the screen. After the user has compared them, he or she should hit return, which should delete the images and plot the next two.

[Ian Culverwell]

Implemented in ROPP5.1. By default, the scripts generate a non-stop series of images, as before. This prevents the test folder from hanging, as compiler tests call buildpack. But if the environment variable ROPP_PAUSE is set to TRUE (or anything, in fact) and exported before running buildpack or make test, then the scripts pause after each pair of figures (new and reference) has been plotted, and wait for the user to hit any key before continuing. In this case, the plots are erased before continuing.

[Dave Offiler]

I suggest that the pause is actually the default action (as being a user-request, users shouldn't have to do anything extra); the non-default action for testing is then needing to set the environment variable -D.