Adding overPotentialFoam and overRhoSimpleFoam and tutorials

.../solvers/basic/potentialFoam/overPotentialFoam/Make/files

...olvers/basic/potentialFoam/overPotentialFoam/Make/options

...rs/basic/potentialFoam/overPotentialFoam/createControls.H

...vers/basic/potentialFoam/overPotentialFoam/createFields.H

...ers/basic/potentialFoam/overPotentialFoam/potentialFoam.C

...s/compressible/rhoSimpleFoam/overRhoSimpleFoam/Make/files

...compressible/rhoSimpleFoam/overRhoSimpleFoam/Make/options

...lvers/compressible/rhoSimpleFoam/overRhoSimpleFoam/UEqn.H

...essible/rhoSimpleFoam/overRhoSimpleFoam/createFieldRefs.H

...mpressible/rhoSimpleFoam/overRhoSimpleFoam/createFields.H

...SimpleFoam/overRhoSimpleFoam/createUpdatedDynamicFvMesh.H

...lvers/compressible/rhoSimpleFoam/overRhoSimpleFoam/pEqn.H

...pressible/rhoSimpleFoam/overRhoSimpleFoam/rhoSimpleFoam.C

tutorials/basic/overPotentialFoam/cylinder/Allclean

tutorials/basic/overPotentialFoam/cylinder/Allrun

tutorials/basic/overPotentialFoam/cylinder/Allrun.pre

...overPotentialFoam/cylinder/cylinderAndBackground/0.orig/U

.../cylinder/cylinderAndBackground/0.orig/include/fixedInlet

...er/cylinderAndBackground/0.orig/include/initialConditions

...overPotentialFoam/cylinder/cylinderAndBackground/0.orig/p