Replace stub_chain
Take source from master, it should be reverted when rspec3.0.0.beta2 or larger is released

rspec-mocks depends on current head of rspec-core
Fix deprecation for rspec/autorun

refs: equiring `rspec/autorun` when running RSpec via the `rspec` command is deprecated
Merge pull request #59 from banyan/more-adjust-rspec3

More adjust rspec3