iterable: expose iterFunc as iterable.Func
iterable: expose iterFunc as iterable.Func

Fixes issue 483.

R=dsymonds, dsymonds1
CC=golang-dev
http://codereview.appspot.com/965044

apparentlymart/golang,pombredanne/go-deleteme,apparentlymart/golang,dsriram/golang,ssrl/go,tv42/old-go,gnanderson/go,gnanderson/go,h8liu/golang,h8liu/golang,tianon/debian-golang,dsriram/golang,tv42/old-go,apparentlymart/golang,nightlyone/golang,ssrl/go,gnanderson/go,h8liu/golang,nightlyone/golang,ssrl/go,ssrl/go,gnanderson/go,bdwalton/debian-golang,gnanderson/go,h8liu/golang,bdwalton/debian-golang,nightlyone/golang,gnanderson/go,apparentlymart/golang,ssrl/go,dsriram/golang,pombredanne/go-deleteme,tianon/debian-golang,nightlyone/golang,tv42/old-go,ssrl/go,tv42/old-go,nightlyone/golang,tianon/debian-golang,tv42/old-go,pombredanne/go-deleteme,tianon/debian-golang,bdwalton/debian-golang,pombredanne/go-deleteme,gnanderson/go,h8liu/golang,apparentlymart/golang,bdwalton/debian-golang,pombredanne/go-deleteme,pombredanne/go-deleteme,tianon/debian-golang,bdwalton/debian-golang,apparentlymart/golang,dsriram/golang,bdwalton/debian-golang,pombredanne/go-deleteme,apparentlymart/golang,h8liu/golang,tianon/debian-golang,dsriram/golang,nightlyone/golang,dsriram/golang,tv42/old-go,ssrl/go,bdwalton/debian-golang,tianon/debian-golang,h8liu/golang,dsriram/golang,bdwalton/debian-golang,tianon/debian-golang,nightlyone/golang,tv42/old-go