doc_table outputs multiline comments and single line comments

[lcaballero]

For clarity doc_table outputs all comments, but it might be useful to ignore multi-line comments for a field so that those comments can be used internally to group fields in the code. For example:

type Conf struct {
    /*** Image config **/
    // MaxWidth controls maximum image width
    MaxWidth int
    // MaxHeight controls maximum image height
    MaxHeight int

    /** User config **/
    // DefaultOwner when no is specified.
    DefaultOwner string
}

The output would skip any /* .... */ comments but put the // comments in the resulting data-structure that is used in the template.