Swapped command line switch in 'echo' call

Upgraded to fish 2.0, which provides built-in echo command, and it cares
about the order of command line switches:
echo -ne '\r'
works as expected (carriage return without newline) while
echo -en '\r'
does not (outputing: "-en \r")
I am not sure if it's a bug or feature, likely the former.