Adds UTF-8 encoding of JavaDoc

Author: viktorklang

spi/build.sbt

@@ -2,6 +2,8 @@ name := "reactive-streams-spi"
 
 javacOptions in compile ++= Seq("-encoding", "UTF-8", "-source", "1.6", "-target", "1.6", "-Xlint:unchecked", "-Xlint:deprecation")
 
+javacOptions in (Compile,doc) ++= Seq("-encoding","UTF-8","-docencoding", "UTF-8", "-charset", "UTF-8", "-notimestamp", "-linksource")
+
 autoScalaLibrary := false
 
 crossPaths := false