add list() around range for py3 compatibility
Tweaks to op_axes stuff to be more readable and slightly faster
update erfa.pyx
minor clarity change
Remove duplicated jd in test
attempt to fix erfa for numpy < 1.8
add TODO about <1.8 support
update erfa
switch from erfa_time to erfa
massage cal2jd tests to be syntax-compat w/ erfa

but still fails (now xfail) due to different error/warning behavior
Add a bit of background info to erfa_time.py