OpenTracing 2.0
Incompatible changes
Update OpenTracing API to 0.33.0 (#177)
The following APIs were removed:
- 
Scope = ScopeManager.active(): no alternative, the reference Scope has to be kept explicitly since the scope was created. 
- 
Scope = ScopeManager.activate(Span, boolean): no alternative auto-finishing has been removed. 
- 
Span = Scope.span(): use ScopeManager.activeSpan() or hold the reference to Span explicitly since the span was started. 
- 
Scope =SpanBuilder.startActive(): use Tracer.activateSpan(Span) instead. 
- 
Span = Tracer.startManual(): use Tracer.start() instead. 
- 
AutoFinishScopeManager: no alternative, auto-finishing has been removed.