Revert "Support conversion of #unstub"

This reverts commit 1daa0216fe07810f3bd4f1e4158927aa33609bb5.

Currently `allow(obj).to receive(:message).and_call_original` does not
work as well as `unstub` sometimes.

https://github.com/rspec/rspec-mocks/issues/613
Bump up version to 1.10.0
Disable shallow clone in demo task

It seems now GitHub rejects push from shallow-cloned repo.
Rename :travis task to :ci
Add a missing spec
Fix a typo in changelog
Fix a typo "convertion"
Refactor Operator
Fix failing spec
Use Parser 2.1.6 or later
Use Parser::Meta::NODE_TYPES
Fix wrong conversion of #have with subject with #[] invocation
Bump up version to 1.10.1
Handle #have with subject with operator method invocation
Bump up version to 1.10.2
Fix a typo in changelog
Normalize spec descriptions
Use \ for string concatenation at the end of line
Replace deprecated Dir.exists? with .exist?
Workaround for IndentHash issue with separator style hash