Prepare changelog
Bump version to 0.2.20
Update to long living backports dependency
Update adamantium and equalizer dependency
Update diff-lcs dependency
Bump to source dependency
Test against 2.0.0 on travis
Use correct latest to_source
Adjust gitignore
Sync devtools
Add explicit rspec dependency
Use Devtools.init_spec_helper
Merge branch 'release-v0.2.20'

Conflicts:
	Gemfile.devtools
	mutant.gemspec