BUG: what to do with astype on datetime64

[jreback]

http://stackoverflow.com/questions/16158795/cant-convert-dates-to-datetime64

prob should raise if u try to convert to something other than object or datetime64[ns]
otherwise can have weird things happen

[jreback]

closed by #3516