Disable SBT forking in Test to fix Travis build

Exception in thread "Thread-1" java.net.SocketException: Connection reset
    at java.net.SocketInputStream.read(SocketInputStream.java:189)
    at java.net.SocketInputStream.read(SocketInputStream.java:121)
    at java.net.SocketInputStream.read(SocketInputStream.java:203)
    at java.io.ObjectInputStream$PeekInputStream.peek(ObjectInputStream.java:2296)
    at java.io.ObjectInputStream$BlockDataInputStream.peek(ObjectInputStream.java:2589)
    at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2599)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1319)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371)
    at sbt.React.react(ForkTests.scala:114)
    at sbt.ForkTests$$anonfun$mainTestTask$1$Acceptor$2$.run(ForkTests.scala:74)
    at java.lang.Thread.run(Thread.java:745)

Author: ashawley

Diff for: build.sbt

@@ -39,3 +39,5 @@ libraryDependencies += "org.scalacheck" %% "scalacheck" % "1.13.2" % "test"
 libraryDependencies += ("org.scala-lang" % "scala-compiler" % scalaVersion.value % "test").exclude("org.scala-lang.modules", s"scala-xml*")
 
 mimaPreviousVersion := Some("1.0.5")
+
+fork in Test := false