OAI harvesting interface

[Ray Plante]

Hi RI reviewers,

Section 3 (Harvesting) needs a little more clarity about what is required 
and what is optional in terms of OAI support, and I just wanted to check 
my own understanding against other folk's.  My understanding is that the 
OAI REST interface--the standard one defined by the OAI people--is 
required, and our SOAP-based version is optional.  Is that your 
understanding as well?  

cheers,
Ray