Move code into Trace folder as opencensus can contain other code in the future

Author: chingor13

composer.json

@@ -1,5 +1,5 @@
 {
-    "name": "opencensus/trace",
+    "name": "opencensus/opencensus",
     "type": "library",
     "description": "OpenCensus Trace Client for PHP",
     "license": "Apache-2.0",
@@ -20,7 +20,7 @@
     },
     "autoload": {
         "psr-4": {
-            "OpenCensus\\Trace\\": "src/"
+            "OpenCensus\\": "src/"
         }
     }
 }

src/IdGeneratorTrait.php src/Trace/IdGeneratorTrait.phpsrc/IdGeneratorTrait.php renamed to src/Trace/IdGeneratorTrait.php

@@ -128,7 +128,11 @@ public static function start(ReporterInterface $reporter, array $options = [])
             ? $samplerOptions
             : SamplerFactory::build($samplerOptions);
 
-        return self::$instance = new RequestHandler($reporter, $sampler, $options);
+        $propagationFormatter = new HttpHeaderFormater();
+
+        self::$instance = new RequestHandler($reporter, $sampler, $propagationFormatter, $options);
+        self::$instance->start($options);
+        return self::$instance;
     }
 
     /**