ENH: Added new function object to calculate the energy spectrum

Description
    Calculates the energy spectrum for a structured IJK mesh

Usage
    Example of function object specification:
    energySpectrum1
    {
        type        energySpectrum;
        libs        ("libfieldFunctionObjects.so");
    }

    Where the entries comprise:
    \table
        Property     | Description               | Required    | Default value
        type         | type name: energySpectrum | yes         |
        log          | write info to standard output | no      | yes
    \endtable

    Output data is written to the file \<timeDir\>/energySpectrum.dat

src/functionObjects/randomProcesses/Allwmake

@@ -0,0 +1,16 @@
+#!/bin/sh
+cd ${0%/*} || exit 1                        # Run from this directory
+targetType=libso                            # Preferred library type
+. $WM_PROJECT_DIR/wmake/scripts/AllwmakeParseArguments
+. $WM_PROJECT_DIR/wmake/scripts/have_fftw
+
+#------------------------------------------------------------------------------
+
+if have_fftw
+then
+    wmake $targetType
+else
+    echo "==> skip randomProcesses library (no FFTW)"
+fi
+
+#------------------------------------------------------------------------------