hoon: use +pow instead of handrolled loop in +ox-co:co
++ ox-co
|= {{bas/@ gop/@} dug/$-(@ @)}
%+ em-co
- [|-(?:(=(0 gop) 1 (mul bas $(gop (dec gop))))) 0]
+ [(pow bas gop) 0]
|= {top/? seg/@ res/tape}
%+ weld
?:(top ~ `tape`['.' ~])
