[dev] RDO::getFields()

[duck]

In RDO I am missing an getFields() method allowing me to get fields as 
array. In a lot of cases I have functons/methods that expects arrays as 
a parameter (like all PEAR classes). So I must always loop every object 
and rewrite its data into an array. I know that exists a SPL function 
iterator_to_array. But it would be much faster just to retrieve the 
fields array rather than let PHP to do it for us.

Duck