* fix: change SpanContext.traceFlags to mandatory
According to spec SpanContext represents the W3C tracestate which
includes traceId, spanId and traceFlags.
As a side effect a new LinkContext types was added as links don't
have traceFlags according to spec.
* chore: review findings, rename TraceFlags.UNSAMPLED to NONE
* fix: build
* fix: tests
* fix: correct merge
Co-authored-by: Daniel Dyla <dyladan@users.noreply.github.com>
* feat: create an api package
* chore: update circle for new api package
* chore: bring back getTracer
* chore: add wrongly removed dev dependency
* chore: review comments
* chore: review comments
* chore: lint
* chore: export all noop implementations
* chore: update API README
* chore: ignore known working links that are not yet published
* chore: add jsdoc for getInstance calls
* chore: add jsdoc for private constructors
* chore: review comments
* chore: fix readme npm url
* chore: fix old readmes without registry
* chore: update api calling convention