Merge commit 'b78e64300d2fcc997c1b07e7b873759dc20c29b5' into develop

* commit 'b78e64300d2fcc997c1b07e7b873759dc20c29b5':
  Miscellaneous fixes

# Conflicts:
#	src/main/scala/io/scalajs/nodejs/stream/Readable.scala

Author: ldaniels528

src/main/scala/io/scalajs/nodejs/Process.scala

@@ -77,7 +77,7 @@ trait Process extends IEventEmitter {
     * Specifying a code to process.exit(code) will override any previous setting of process.exitCode.
     * @example process.exitCode
     */
-  def exitCode: Int = js.native
+  var exitCode: Int = js.native
 
   /**
     * TODO find documentation for this property

src/main/scala/io/scalajs/nodejs/stream/Readable.scala

@@ -190,7 +190,7 @@ object Readable {
       * flowing mode. Data will then be passed as soon as it is available.
       */
     @inline
-    def onData(listener: Buffer | String | Any => Any): readable.type = readable.on("data", listener)
+    def onData[A](listener: A => Any): readable.type = readable.on("data", listener)
 
     /**
       * This event fires when there will be no more data to read. Note that the 'end' event will not fire unless the