Update centaur_test.rb

test_after_laying_down_it_is_not_standing was missing a skip and centaur instance
Fixed broken tests
In test_it_can_lay_down, added missing assert
In test_after_laying_down_it_is_not_standing, added following:
Missing skip
Missing initialized Centaur
Merge pull request #14 from dglunz/patch-1

Update centaur_test.rb
Merge pull request #15 from VikiAnn/fix-broken-tests

Fixed broken tests
Workshop pair programming at Turing
Add a pipe for the wizard!

* Test with rspec
Clean up pipe class comments