Update regression tests for new output mechanism and to use --exec flag

  Create a branch to implement things that we need for the Vis 2012 paper

  Add documentation about running scripts

  Add generated OpenCL file to cleanup

  Added runtime arguments to regression-test run script

  merging changes from pure-cfg

  Added support for hest-based command-line arguments to trunk.  Also switched
  output filename to prog.txt (from mip.txt)

  Adding support for assignment operators to the trunk.

new semantics for unu 3op max_sm

changed output image size from 200 to 201 to avoid sensitivity to FP error on inside() test, and made assess.sh slightly more tolerant of FP error

test more lenient WRT FP round-off

test more lenient WRT FP round-off

making test more permissive of rounding errors

a simple volume-rendering test

test axis dataset; human-readable nrrd file

have tweaked data

tweaking data

another test dataset

making ring dataset less isotropic

  Added script to run a single regression test

  tweaking the regression-test script

some comments

making slow tests run faster

another test

new datasets

new tests

more tests

basic test of 3D convolution

  added the ability to test a different version of the diderot compiler

  minor tweaks of messages

  added README for tests

  Scripting support for regression tests

  more scripting work

  Working on testing script

  Move regression tests into the tests subdirectory so that we can more easily
  script the testing process.

data for 2D convolution tests

beginnings of some regression test stuff