test: New directory for model tests and validation

The initial set of cases in the test directory are aimed at testing the
reactingEulerFoam populationBalance functionality.

Patch contributed by Institute of Fluid Dynamics, Helmholtz-Zentrum
Dresden - Rossendorf (HZDR) and VTT Technical Research Centre of Finland Ltd.
Integrated with the "tutorials" functionality by CFD Direct Ltd.

bin/tools/CleanFunctions

@@ -39,7 +39,9 @@ cleanTimeDirectories()
         rm -rf ./${timeDir} ./-${timeDir} > /dev/null 2>&1
         zeros="0$zeros"
     done
-    rm -rf ./[1-9]* ./-[1-9]* ./log ./log.* ./log-* ./logSummary.* ./*.xml ./ParaView* ./paraFoam* ./*.OpenFOAM ./*.blockMesh ./.setSet > /dev/null 2>&1
+    rm -rf ./[1-9]* ./-[1-9]* ./log ./log.* ./log-* ./logSummary.* ./*.xml \
+       ./*.dat ./*.eps ./ParaView* ./paraFoam* ./*.OpenFOAM ./*.blockMesh \
+       ./.setSet > /dev/null 2>&1
 }
 
 cleanDynamicCode()