Make looksee#ls method worked together with pry 0.10.1 ls command.

Pry 0.10.1 change command implementation.

With old looksee, it will make ls command in pry terminal not work.

This change will make ls command still work like this: `` (pry):0> ls``,
and Looksee#ls can work like this ``(pry):0> "hello".ls``, just same as worked with pry 0.9.12.