Globally rename rcov to test_coverage, except when rcov-specific
Extract out RCovFormat handling logic
Spec out our own simplecov to rcov formatter
Ensure coverage css included in coverage report
Remove unused css from analyzed file report
Add really basic simplecov formatter tests
Add simplecov to gemspec; update formatter docs
Dump external metrics as binary
Merging master into this branch
Fix example discovered by usage_test