Replaced writeOutput with atomically loaded function, refactored Makefile + added code coverage generation

chore: Format code

tests: Fixed TestPrintfStackTraceAlways to actually assert output, remove dead code and clean up comments

Add tracing regions, colorized output, and benchmarks

Merge pull request #1 from jelder/jelder-patch-1

This fixes two minor Markdown issues:

README: added part explaining the nuance of compile time elimination

README: fix link to sync.Locker

README: finishing touches

initial commit