Improve SexpNode#deep_copy

- Remove useless guard
- Make type check idiomatic
- Re-implement SexpNode#deep_copy without YAML
Merge pull request #205 from troessner/improve-sexp-deep-copy

Improve Sexp#deep_copy
Add --single-line option for reporting (github Issue #206)
Merge pull request #208 from apiology/single_line_report

Add --single-line option for reporting (github Issue #206)
Bump version to 1.3.4.
Added more robust ControlParameter detection.
Merge branch 'ControlParameter_detector' of https://github.com/gilles-leblanc/reek into ControlParameter_detector