DataEntry: Base the name of the coefficients sub-dicts on the entry name rather than the type name

This allows for more than one of these data types to be specified in a dictionary
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1652

e.g.
        <entryName> csvFile;
        <entryName>Coeffs
        {
            nHeaderLine         4;
            refColumn           0;          // reference column index
            componentColumns    (1 2 3);    // component column indices
            separator           ",";        // optional (defaults to ",")
            mergeSeparators     no;         // merge multiple separators
            fileName            "fileXYZ";  // name of csv data file
            outOfBounds         clamp;      // optional out-of-bounds handling
            interpolationScheme linear;     // optional interpolation scheme
        }