v0.2.0 — Support no-clean-rebuild

• Support --no-clean-rebuild to speed up coverage when the test artifacts are already clean-rebuilt.
• Added --print-install-kcov-sh to emit sh code to install kcov.

v0.1.0 — Initial release

• Support collecting coverage with kcov v31.
• Should support all coverage functions provided by travis-cargo (collect coverage, merge, upload to coveralls), aside from installing kcov.