Removed recursion and a few tweaks

Hi Nic,

I was playing with kv this afternoon after you reminded me of its existence. There's a nice idiom for stepping through a plist with loop on/by 'cddr. There wasn't a test for kvplist->alist so I added one and in testing I found that keyword->symbol could also act on a non-keyword so I put a check and a test in for that too.

Do what thou wilt and all that!