This reverts commit c5bea524.

This reverts commit b18f6cc1.

- easier to clean, avoid confusion with 'real' applications, etc.

Exception: applyWallFunctionBoundaryConditions.C cannot split #include
directives.

- change system/controlDict to use functions {..} instead of functions (..);
  * This is internally more efficient
- fixed formatting of system/controlDict functions entry

- pedantic change: use 'return 0' instead of 'return(0)' in the applications,
  since return is a C/C++ keyword, not a function.